D. H. Mahan, A Treatise on Field Fortifications, Containing Instructions on the Methods of Laying Out, Constructing, Defending, and Attacking Intrenchments, with the General Outlines Also of the Arrangement, the Attack, and Defence of Permanent Fortifications will be cited as [Mahan, Treatise on Field Fortifications]

Capt. J. C. Duane, Manual for Engineer Troops will be cited as [Duane, Manual for Engineer Troops]

TRAVERSES are portions of parapets, which cross the breadth of the covered-way, at the salient and re-entering places of arms.  Other traverses are also placed between these, where necessary, to afford proper protection.  Traverses are thrown up, to bar enfilade fire, along any line of work or passage which is liable to it.

[Scott, Military Dictionary, page 625]

Traverses were simply mounds of earth built to protect against flying objects, primarily, but not necessarily, enemy fire.

Traverses built between artillery emplacements to contain the damage caused by premature firing [rupture] or other unintended ordnance explosions, such as incoming fire striking an ammunition chest

Traverses Built Between Artillery Positions - Petersburg - Union Fort McGilvery

Plate XII - Engineer and Artillery Operations Against the Defences of Charleston Harbor in 1863 ... &c., Q. A. Gillmore

Within a fortification to protect a portion of the terre plein from incoming fire

Traverses are placed at intervals along the covered-ways; they serve to intercept the projectiles which enfilade the covered-ways, and also to defend them foot by foot; enabling the troops to retreat from one part of the covered-way behind the traverse under the protection of its fire.

[Mahan, Treatise on Field Fortifications, page 141]

… traverses must be formed from distance to distance to guard against enfilade fire.

These traverses are said to be “en cremailleres” when placed alternately on the right and left of the sap, “tournantes” (winding) when left in the middle of the sap, which surrounds them entirely.

The position of the traverses and returns should be so situated that a man standing in any part of the sap cannot be
seen from the place, and that projectiles cannot ricochet on the bottom.

[Duane, Manual for Engineer Troops, pages 157 - 158]

Traverses (red) "Tournantes" - Petersburg - CSA lines between Elliott's and Rive's Salients

Traverses - Protecting Artillery Position Against Reverse Fire - Petersburg - CSA Battery 45

Spaced at intervals, perpendicular to a line of fortifications, to protect against enfilade fire

Traverses Built Along an Infantry Parapet

Traverses were built all the way up to a parapet or built with a small space, typically two feet, between parapet and traverse.

Traverses - Built to Parapet & Built away from Parapet - Petersburg - Union Fort Sedgwick

If built with extra thickness or otherwise strengthened [most commonly by an additional row of gabions], traverses were termed “splinter-proof”.

The width of a traverse depended on the amount of protection desired:

• 10 feet for interior explosions and small arms fire
• 12 – 16 feet for artillery fire.

The height of a traverse also reflected the situation:

• Protecting a barbette battery – six feet above pan coupe
• Along an infantry parapet – 18 inches higher than infantry parapet
• Protecting against reverse fire – see Mahan’s description below

Traverses were also built as multipurpose structures – magazines were often built into [under] them.

Mahan’s guide to calculating the height of parapet and traverse:

Suppose a section of the work (Fig. 17) to be made by a vertical plane, passing through the highest points o and o’.  If in this plane a vertical, a-b, be drawn, corresponding to the capital of the work, and eight feet be set off on this vertical from
the point a, and two verticals be drawn through the points o and o’, and five feet be set off on each of them; and then the points c and c’ be joined with d, it is obvious that the interior crest of the parapet a, being placed on the line c-d, will screen all the ground in the rear of it, as far as the capital, from the direct fire from o.

This is really bad.  I can’t find a copy of Mahan’s Treatise with the right side of the drawing visible.  If you have an active imagination, you can see it is the mirror image of the left side, labels o’ and c’.

The parapet B being regulated in a similar manner, will screen all the ground behind it as far as the same line.

But the fire from o’ would take the parapet A in reverse, and that from o the parapet B; to prevent this, a covering
mass, denominated a traverse, must be erected on the line of the capital, and a sufficient height be given to it to screen both A and B from a reverse fire.

To effect this, let eighteen inches be set off above the interior crests of A and B; the point e being joined with c’, and the point e ‘ with c; it is here also obvious, that if the top of the traverse be placed on the line c-c’, it will effectually screen both the parapets from all reverse fire; because every shot that strikes the top of it will pass at least eighteen inches above the two parapets, and since the banquettes are four feet three inches below the interior crests, the shot must pass five feet nine inches above the banquettes, which will be quite sufficient to clear the heads of the men when on the banquettes.

This illustration explains the spirit of the method of reverse defilement.  The operation itself is performed in the following manner.

Mahan’s methodology determines the proper height of a parapet in a fortification open to the rear, as shown in Fig. 16.

Simple Lunette - Open Gorge (A - E)

The correct parapet height will protect anyone within the fortification, but not behind it.

When determining the height of a traverse, Mahan assumes there is a second parapet, the correct height of the traverse shielding it from fire, as shown in Fig. 17.  Back to the Treatise.

Poles are planted at the points A,B,C, &c, and one at the point F, where the lines of the capital and gorge intersect.  On the pole F, a point is marked three feet above the ground, and a point is likewise marked on the pole at C, which should be one foot six inches higher than that on F; that is, if the ground between the two poles be level, the point on C will be four feet six inches above the ground.

Two stout pickets may next be planted between F and C, and a cord, or a straight edge, be fastened to them, so as to be in the same line as the points marked on the poles.

Observers are then placed at the poles A and B; and another places himself behind the cord so as to bring the posts o, [Fig. 17] A, and B, in the field of vision with it; then shifting the position of the eye until the cord is brought tangent to the highest point on o, he directs the observers at A and B, to mark on the respective poles the points where the plane of vision intersects them.

This operation will determine the rampant plane for one half the work A-B-C-F, that for the other half will be determined by a similar process.

If then a distance of five feet be set off on each pole above the points thus determined, these points will fix the position of  the interior crests.  It is obvious that the interior crest of the part A-B-C is not in the same plane as that of the part C-D-E.

These two planes are denominated planes of direct defilement.

To determine the height of the traverse is the next step.  To do this, the height of the tread of the banquette is ascertained on the three poles, B, C, D, and a distance of nine inches is set off on each pole above the tread, between the points thus determined a cord is stretched, or if the distance he too great for this, two pickets may be placed between B and C, and a cord, or straight edge, be fastened to them in the required direction.

An observer is then placed at the pole F, and another places himself behind the line B-C, so as to bring the cord, and the points o’ [Fig. 17]and F, in the field of vision; he then shifts the position of the eye until the cord is brought to touch the point o’; he then directs the observer at F to mark the point on the pole where it is intersected by the plane of vision.

A similar operation is performed with the point o, [Fig. 17]and the face C-D, and above the highest point thus determined on F, a distance of five feet is set off for the top of the traverse at F; and five feet nine inches is set off above the tread of the banquette at C for the top of the traverse at that point.

The planes which determine the top of the traverse, are termed planes of reverse defilement. [italics added]

[Mahan, Treatise on Field Fortifications, pages 26 - 29]

Clear as mud.  It would take some practice to do this in the field.  We can try it in a virtual world, though.

How about this: in the Petersburg lines, Union Fort Haskell [be sure and visit - well preserved - tour stop in the Eastern Front unit of Petersburg National Battlefield] was dominated by a Confederate Battery on ground within Blandford Cemetery today [nothing to see but recent burials].  Distance = 2,584 feet.  Elevation difference = 36 feet [11 meters].  With these numbers, maybe we can compute the proper height of Haskell’s parapet facing the Confederate Battery.  Then we’ll try to compute the height of a traverse protecting the opposite parapet from reverse fire.

If we follow Mahan’s directions, on a straight line from 5 feet above the ground level of the Confederate battery [see Fig. 17 - a generous allowance for muzzle height] to a point 8 feet above the ground on the rear line of Fort Haskell, the parapet would have to be 10.7 feet high.  In this scenario, a projectile would pass 18 inches above the interior crest of the protected parapet – way too close if it was our head firing over the top.

Theory and practice, we find repeatedly, are not close personal friends.  The actual parapet of Fort Haskell was 6.5 feet high.  Haskell did have small traverses t0 protect some infantry parapets from enfilading fire, but nothing designed along Mahan’s concept.

Let’s try another example where the works were farther apart.  Behind Elliott’s Salient [on Petersburg NPS land but no visible remains] a Confederate battery had one embrasure pointed directly down an embrasure of a small Union work 3,634 feet away [mostly under I-95 today].  The Confederate battery was 2.7 meters higher than the federal battery.  Round up the difference of 8.86 feet to 9 feet.

Using the same concept, a straight line from a point 14 feet above the ground [9 feet + 5 feet to a muzzle] to a point 8 feet above the ground along the line of the gorge of the Union lunette, the parapet would have been theoretically built to a height of 8.4 feet.  Eight feet was a common practice per the drawings of Petersburg Federal fortifications.

Now for the traverse.  It depends on the distance between the two parapets and where the traverse is situated.  In the Haskell example, to protect an interior crest of 6.5 feet high [typical for an infantry parapet closing a gorge] from reverse fire and assuming a projectile would clear the forward parapet [height would need to be less than 10.7 feet], the traverse would need to be between 10.7 feet and 8 feet high.  Centered in the fortification = 9.3 feet.

In the second example, if the rear parapet was 6.5 feet high and 150 feet from the forward parapet, a traverse would need to have been between 8.4 feet and 8 feet.  Centered between the two parapets, 8.3 feet.

The protective capability of traverses was reduced but not eliminated by using projectiles with a sharp rate of descent.  Mortars fit the bill perfectly.  As the Petersburg “siege” progressed, mortars became the most effective weapon for both sides in the battle between the entrenched positions.  Field artillery still ruled the day in open-field fights.

Traverses were constructed with any type of revetment, but a combination of fascines and gabions or timber were most frequently used.

Traverse Built with Gabions

Traverses. Those which are constructed to cover the flanks of the guns from an enfilade fire, are usually what are termed gabionades.  To form a gabionade, gabions are placed in a row, side by side, enclosing a rectangular space of about twelve feet in width from out to out, and about twenty-four feet in length, perpendicularly to the epaulment.  A second row is placed within this and touching it.

The area thus enclosed is filled in with earth, to a level with the top of the gabions.

Four rows of large fascines are next laid on the gabions, to support a second tier consisting of one row.  The second tier is filled in like the first, and the earth is heaped up on top, making the gabionade nearly eight feet high.  The work will be expedited by throwing up the greater part of the earth before placing the second tier.

Splinter proof traverses may be made by placing three thicknesses of gabions side by side filled with earth, with a second tier of two thicknesses on top.

[Mahan, Treatise on Field Fortifications, pages 59 - 60]

A course of fascines is employed to form the base of the revetment, as in the previous case.  The arrangement of the first course of gabions is shown in the figure.

When nearly filled, the opposite rows should be tied together and across the corners, with wire or rope; when filled they are crowned with fascines.

In the second course there is one less gabion on each side than in the first.  The two rows meet at top, where they are tied together.

The earth is rounded over the top to the depth of 18″.

[Duane, Manual for Engineer Troops, pages 250 - 251]

Examples of Traverses Built with Gabions

A series of Confederate traverses built with gabions, fascines and timber.  These were about 7 feet in height, arranged along an infantry parapet.  This may be the actual field fortification shown in the map section captioned “Traverses Built Along an Infantry Parapet” presented above.

Traverse Built with Fascines

SPLINTER-PROOF TRAVERSES are rectangular, they are 16′ x 6′ at the base, and 14′ x 4′ at top, a passage 2′ wide is left next to the parapet.

The first course of fascines is half-imbedded in the ground and secured by pickets, the earth filled in and rammed.  The other courses are laid in a similar manner.

In every second or third course the opposite fascines of the long sides are tied together with wire or rope, those of the short sides are anchored.

[Duane, Manual for Engineer Troops, page 249]

Revetment? Anything at hand.  Traverses were supported by timber, lumber, hurdle, cotton bales, sandbags and nothing at all.  Here are a variety of innovations found among the myriad of photos online:

HURDLE

SANDBAGS

TIMBER

MIX

HEY, THAT ONE LOOKS FAMILIAR

NO REVETMENT

D. H. Mahan, A Treatise on Field Fortifications, Containing Instructions on the Methods of Laying Out, Constructing, Defending, and Attacking Intrenchments, with the General Outlines Also of the Arrangement, the Attack, and Defence of Permanent Fortifications will be cited as [Mahan, Treatise on Field Fortifications]

Capt. J. C. Duane, Manual for Engineer Troops will be cited as [Duane, Manual for Engineer Troops]

The term “scantling” appears often in the period literature.  It refers to lumber cut to size, i.e. 2 x 4, 2 x 6, 2 x 10, etc.  Readers should note dimensioned lumber was cut to actual size, so a 2 x 12 was actually 2 inches by 12 inches, not the trimmed 1 3/4″ x 11 3/4″ we buy today.

Powder magazines

The main objects to be attended to in a powder magazine are, to place it in the position least exposed to the enemy’s fire; to make it shot proof; and to secure the powder from moisture.

If there are traverses, such for example, as are used in defilement, the magazines may be made in them; or they may be placed at the foot of a barbette; or, in dry soils, be made partly underground.

The magazines should be at, least six feet high, and about the  same width within; its length will depend on the quantity of ammunition.  It may be constructed of fascines, gabions, or coff’er-work, or any means found at hand may be used which will effect the end in view.

If fascines are used, the sides should slope outwards to resist the pressure of the earth; the fascines should be firmly secured by pickets and anchoring withes.  The top may be formed by a row of joists, of six-inch scantling, placed about two and-a-half feet apart; these should be covered by two layers of fascines laid side by side, and the whole he covered in by at least three feet thickness of earth.  The bottom should be covered by a flooring of joists and boards; a shallow ditch being left under the flooring, with a pitch towards the door of the magazine, to allow any water that might leak through to be taken out.  A thatch of straw might be used on the inside, but it is somewhat dangerous, owing to its combustibility; hides or tarpaulins are better, and will keep out the moisture more effectually.

Magazines - Fascines

A coffer-work is formed by making frames of six-inch scantling; each frame is composed of two uprights, termed stanchions, and a cap and ground-sill, well nailed together; it is six feet wide, and six feet high in the clear.  These frames are placed upright, and parallel to each other, about two-and a-half feet apart; they are covered on the top and sides by one-and-a half -inch plank, which is termed a sheeting.  The magazine otherwise is constructed as in the last case.

Magazines - Coffer-Work

When gabions are used, a hole is usually dug in the ground to form a part of the magazine; the gabions are placed in two rows, side by side, around the hole, and are filled with earth.  The top is formed as in the case of fascines.

Magazines - Gabions

The mouth of the magazine is covered by a splinter proof shelter. This is constructed by taking scantling eight by ten inches, cut into suitable lengths, and placing it in an inclined position, so as to cover the mouth, and leave an easy access to it.  The pieces, usually, are inclined 45°, and are placed side by side; they are coveted by at least two feet of earth, or sods; and hides or tarpaulins are thrown over the whole.

Splinter-Proof Cover for Magazine Entry

Splinter proof blinds are mainly intended to afford a shelter against the fragments of hollow projectiles that explode in the work.  They may be used as a kind of barrack for the troops; and to store provisions, &c.

[Mahan, Treatise on Field Fortifications, pages 58 - 59]

MAGAZINES
Are usually built fifteen yards in rear of the parapet of the battery or communication, sometimes at the end of the battery parapet or in that of the communication ["covered way" or "boyeaux" - a trench protected from enemy fire connecting a battery with other elements in a line of field fortifications].

The figure represents a rectangular magazine in rear of the parapet.  An excavation 4′ deep receives the five mining
frames, each composed of a cap-sill 6′ X 8″ X 6″, two stanchions 4′ 6″X6″X6″, and one ground-sill 5′ 6″X6″X3″. The intervals between the frames are 2′ 6″.

Framing - Set 2' 6" Apart

Magazine Layout

The ground-sills are brought to the same level, and surrounded with sheeting one inch thick, and covered with timber or plank at least 6″ thick.

The frames for the communication may be of somewhat smaller scantling, that of six inches square will answer for the cap-sills.  These frames are 2′ 6″ wide in the clear, and of the same height as those in the magazine.  The sheeting is also the same.

The roof may be still further strengthened by layers of timber or fascines.  The whole must be covered with earth to the depth of 7′.

As a precaution against moisture, a mound of earth is raised over the magazine, in the form of a roof, and about 2′ high in the middle, over which a tarpaulin is laid and the remainder of the earth thrown on.

The earth for this covering is partly furnished by the excavation for the magazine, and the remainder from a trench cut around it, leaving a sufficient berme to prevent the embankment caving in.

When the soil is favorable the magazine may with advantage be sunk two or three feet lower.

The magazine is connected with the battery, by a trench 4′ wide, and 3′ 6″ deep, whose direction is such as to avoid being enfiladed.

The entrance to the covered passage should be turned from the enemy.  The passage having a return or change of direction, so that there may be no danger of fragments of shell finding their way into the magazine.

When suitable timber cannot be obtained for the above construction, those shown in the following figure may be used, in which the interior revetment is principally of fascines and gabions.

The dimensions given for the preceding constructions are not invariable.

In ordinary soil, the thickness of parapet and covering of the magazine, are a sufficient protection against the artillery
usually employed in the defence of a work.  In the case however, of a light soil, or when the enemy is provided with very heavy ordnance, as in the siege of Sebastopol, this thickness may frequently require an addition of six or eight feet.

[Duane, Manual for Engineer Troops, pages 261 - 265]

MAGAZINES

Powder magazines ought to secure an unobstructed circulation of air under the flooring as well as above.  The magazine should be opened and aired in clear dry weather; the ventilators should be kept free; and no shrubbery or trees should be allowed to grow so near as to protect the building from the sun.

All batteries of attack require magazines capable of holding ammunition for daily consumption. Fig. 150 is a section of two strong splinter-proof timbers, say 8 to 9 feet long, and 9 to 12 inches in breadth and thickness, resting on sleepers, and giving an interior space of about the dimensions seen in the figure, covered with one or two tiers of fascines, and over them 3 or 4 feet of dung or stiff earth; this simple construction would answer in many cases.

By some persons it is considered better to have two small magazines in a battery, made of very stout mining cases, and constructed in the epaulements.  Sir John Jones, in his work on “Sieges,” says :

“Splinter-proof timbers for magazines were cut 12 feet in length, and from 8 to 10 inches in breadth and thickness, and were placed against an epaulement, or  parapet, at an angle making the base equal to half the height.  They were then covered with a tarpaulin, extending well over the top of the epaulement upon which were laid one or two rows of filled sand-bags, so as to prevent the possibility of the tarpaulin being cut by splinters of shells.  A second tarpaulin was usually thrown over the exterior in rainy weather. On this construction, the magazines were found to be perfectly dry, and sufficiently spacious, and of the strength no doubt can remain, as the sand-bag covering was frequently knocked off by large shells, and in no instance were the  splinter-proofs broken.  The best situations for magazines are on the flanks of the batteries.  Nothing can be worse than to place them in rear of the centre of a battery, as then every cartridge has to be carried along the most exposed and dangerous part of the battery, and the number of accidents and casualties which arise therefrom is very great indeed.  The artillery always preferred having two magazines formed, rather than to have one exceeding 10 or 12 feet in length; when two were made, they were placed one on either flank, a situation which was found to answer extremely well.”

[Scott, Military Dictionary, pages 394 - 395]

Magazines were not built when a unit was on the move, as in most combat situations – in those cases, ammunition was carried one firing at a time from a piece’s limber chest.  It is common, for example, to find artillery positions protected by epaulments without magazines along the lines of fortifications built during the Overland Campaign.

In situations where the field fortifications were more permanent in nature, such as the lines at Petersburg, magazines were typically located and designed by a supervising Engineer.  Flexibility and innovation rather than rigidity rule the day for field fortifications.  There was always a shortage of “practicing” engineers.  Again, we remind:  many officers other than the designated Engineers were also West Point graduates.  Find a need, fill a need.  Circular No. 96, Headquarters Fifth Army Corps, July 29, 1864:

While remaining in our present position all the artillery belonging to the corps will be under the special direction of Colonel Wainwright, chief of artillery.  He will supervise the construction of magazines and all other necessary preparations in and around the batteries and when in position.

[OR Series 1 Vol. 40 Part 3 Chapter LII page 607]

To put the Circular in context, read the July 1864 entries in A Diary of Battle, the Personal Journals of Colonel Charles S. Wainwright 1861 – 1865, edited by Allan Nevins.

Building a magazine satisfied two objectives:

• Removed a precious commodity, the horses, from counter-battery fire
• Facilitated the storage of more ammunition than could be stored in the limber and caisson chests

It was also a common practice to remove ammunition chests from limbers and place them in a hole in the ground near a field piece.

Multiple magazines would be built:

• Keep a reasonable walking distance – ease of access – minimize exposure of gun crews to enemy fire
• For different kinds of ordnance

In some period photos, we see a shelf by the entrance with ordnance on it – a quick way for anyone to see what was inside.

Engineer’s drawing on Union Fort Dushane.  Separate magazines built for easy, close access from each bastion.

This engineer’s drawing of Union Battery No. 12, between Forts Stedman and Haskell, is an example of multiple magazines built for different kinds of ordnance.

Multiple Magazines = Different Ordnance

Magazines were built with a variety of different characteristics.  At Petersburg, we find them as stand-alone structures, built into (under) traverses, in conjunction with bomb-proofs (both as parallel and end-to-end schematics) and even built directly under gun platforms they served.  Entries ranged from straight stepped drops to the powder chamber,with one or more turns.  The following clips from engineers’ drawings show a gambit of constructions.

For this last example, we have a period photograph.

Magazines were roughly the same size, designed: “…  so that each gun should have 150 rounds, including that in the limbers, which in most cases were left in the forts.”   Similar instructions can be found in communications of the Army of the James, operating north of the Appomattox River.

[OR Series 1 Vol. 40 Part 1 Chapter LII page 282 - report of Brig. Gen. Henry J. Hunt, Chief of Artillery, Army of the Potomac]

At Petersburg, magazines dug into the ground were standard practice.  Where we can discern the depth of the excavation, those designed by the engineers of the U. S. Engineer Battalion were sunk either 3 or 4 feet with a total interior height of 6 to 7 feet.

Look for a rule, find an exception.  From the report of Col. Henry L. Abbot, commanding Siege Train, for the period June 14 – October 31, 1864:

As most of the magazines [in batteries manned by his command, the 1st Connecticut Heavy Artillery] have been made under the superintendence of my officers, it may be well to state that the plan adopted, putting them in secure positions and making the chambers entirely below ground, roofed by heavy logs, and covered by dirt some six feet thick, has been found to be both simple and safe.  Boards have seldom been used either for the sides or the floor, which is made to drain into a barrel near the entrance.  The usual dimensions, in the clear, have been six feet wide by five feet deep, length to vary according to capacity required.  In no instance has one of them blown up, although often hit by the rebel projectiles; and even in heavy rains, such as that of August 15, at Petersburg, when several soldiers in the low bottom were washed away and drowned, no loss of ammunition, except in one battery, has occurred from leakage.

[OR Series 1 Vol. 40 Part 1 Chapter LII page 668]

On the Confederate front, this July 16, 1864 directive from Maj. Gen. B. R. Johnson to Col. P. F. Faison, commanding Ransom’s Brigade:

You will immediately send from your reserve regiment seventy-five men and three officers and the proper number of non-commissioned officers for fatigue duty, to work on the mortar battery in rear of your headquarters.  You will continue to supply the detail until the mortar pits and magazine are completed.  The mortar pits are to be six feet deep and the magazine five feet.  On yesterday similar orders were sent to you from these headquarters.  You will state in writing why these orders have not been complied with, and why there has been no detail from your command on this work today.

[OR Series 1 Vol. 40 Part 3 Chapter LII page 773]

Subtle, eh?  Well, there were good reasons for the General’s apprehensions.  See Wasted Valor, The Petersburg Campaign June 15 – 18, 1864, by Thomas J. Howe.

Contrary to Col. Abbot’s rosy report, not all magazines survived wet conditions.  An inspection report from Capt. F.M. Edgell to Headquarters, Artillery Brigade, 2nd Army Corps, dated September 18, 1864:

As the result of an examination of the inclosed work on the left of the plank road known as Fort Crawford, I have the honor to report that in my opinion the work in its present condition is incapable of a proper defense with artillery.  The following improvements seem to me to be necessary:  First. The banquette at the north and west faces should be of sufficient depth to permit the use of artillery at any point on those faces, or at least the present platform should be so extended as to allow four more guns on each face and facilitate the use of those now in position.  Second. Magazines should be erected of sufficient capacity to contain the artillery ammunition required there by permitting the caissons of the light batteries occupying the work to be sent to the rear, as they are not sufficiently covered in the work.  The only magazine fit for present use is small, ill-drained, and now filled with infantry ammunition, and one situated near the southeastern angles is partially filled with water and in a stinking condition.  If the magazines were situated near the north face they could be easily drained by tunnels.  Bomb-proofs should take the place of the traverses at the western face.  Other improvements than those above mentioned would perhaps suggest themselves to the eye of an engineer.

[OR Series 1 Vol. 42 Part 2 Chapter LIV page 902]

This report from Bvt. Maj. Peter S. Michie to Department of Virginia, Engineer’s Office dated March 23, 1865 is indicative of on-going problems related to water in the excavated magazines: “At Fort Brady the work to the bank in front of embrasures is finished and the magazine has been drained.” [OR Series 1 Vol. 46 Part 1 Chapter LVIII page 376]

Like all field fortifications, magazines required ongoing maintenance.  As the troops went into winter camp, this became more problematic.  By January, commanders were requesting inspection reports as the first step in returning their earthworks to satisfactory condition.  On January 11, 1865, Maj. Gen. Humphreys, now commanding the 2nd Corps, wrote the the Army’s Chief Engineer:

Colonel Hazard, chief of artillery, reports to me that the parapets of all the redouts require some repair as well as the magazines; that the magazines of Forts Fisher and Welch must be rebuilt – the first entirely, the second chiefly; the first is already provided for; the second, and the repairs generally of the works, Colonel Hazard can assign artillery officers to attend to, if you will have a non-commissioned officer ordered to report to him for each of the works in the front and rear line to see that the details of the works are properly attended.  An engineer officer might take the general charge of all.  If, however, you prefer the engineer officers to take the matter in exclusive charge, let me know.  I have not yet received from the division commanders the reports respecting the condition of the intrenchments held by them.  I have sent for that of the First Division, but as there is some delay in receiving it I do not wait longer.  I understand one has gone forward to your office.

[OR Series 1 Vol. 46 Part 2 Chapter LVIII page 95]

In most instances, we don’t know for sure if the magazines were built using gabions and fascines, timber or lumber.

At Petersburg, gabions were used extensively for fortifications (and magazines, but this is an educated guess) from the Appomattox River through Fort Sedgwick.  This section of the Union lines was secured early in the campaign, many of the earthworks built before the massive supply chain with its ability to deliver lumber on demand was up and running, and constructed under combat duress as the opposing lines were very close together.  In the photo above, we see gabions holding back the earth over the entrances to the magazines.

For magazines built later in the “siege”, we assume timber and lumber were used.  The supply chain was extended as fast as the lines, the sawmills and lumber docks were in full operation, and the threat from enemy fire was diminished as the opposing lines drifted farther apart.  The supervising engineer ordered 200 feet of lumber for a magazine at Fort Howard on January 4, 1865 [ordnance removed a month later because the magazine was "defective", see below]. [OR Series 1 Vol. 46 Part 2 Chapter LVIII page 31]

We just can’t be sure.  Gabions and fascines were still being used in the Fort Fisher upgrade in February 1865.  The small numbers mentioned suggest revetment for embrasures, but the number also could have included at least one magazine.

During the week 204 fascines have been made and delivered at Fort Fisher and the eleven-gun battery; 693 gabions have also been made and brought into camp; of these, 417 have been issued for Fort Fisher and for repairing the works on the Ninth Corps front.

[OR Series 1 Vol. 46 Part 1 Chapter LVIII page 161]

In a few cases we can place some reliance on engineers’ drawings.  While they typically did not profile magazines, they would do so if the structure was parallel to a bomb-proof.  This example, from Fort Mieckle, indicates timber construction:

From the drawings of the ring of forts built around the supply base at City Point, this example of a magazine built with lumber:

Despite their use in the example above, wooden floors were not commonly used at Petersburg.  We cannot prove it, but surmise they were used when necessary.  Union Forts Davis, Alexander Hays and Howard were built on low, wet ground and the engineer’s drawings show extensive drainage systems – good candidates for solid floors.  It’s possible some of the ground in this area wasn’t suitable for excavated magazines at all.  From a report dated February 1, 1865 written by Bvt. Maj. Gen. Wheaton to Headquarters, 1st Division, 6th Army Corps:

Fort Howard and Batteries 25 and 26 were garrisoned in December. when under the command of General Humphreys, the strength of each being alike, viz, 150 men.  The extra ammunition ordered to be stored in these last-named works for the garrisons, pickets, and reserve force was returned to the division ordnance storehouse, as the magazines were defective.

[OR Series 1 Vol. 46 Part 2 Chapter LVIII page 346]

The two magazines at Fort Morton [engineer's drawing and photo above) if not originally built with solid flooring, were so outfitted on January 17, 1865. [OR Series 1 Vol. 46 Part 1 Chapter LVIII page 157]

Mahan’s text would protect the entry of a magazine with a sloped “splinter-proof”.  We don’t see any indication such covers were used at Petersburg.

In fact, magazines were first built without any doors.  Within six weeks, however, the Army of the Potomac’s Chief of Staff wrote to City Point: “Please procure forty sets of hinges and hasps and padlocks for magazine doors.” [OR Series 1 Vol. 40 Part 3 Chapter LII page 389]

Apparently, it was easier to raid a neighbor’s magazine than wait for your own resupply.

To end this article, we present some material addressing why there was at least seven feet of earth piled over a magazine.

In the first instance, Maj. Thomas Lincoln Casey, Corps of Engineers, is explaining why Gen. Butler’s plan to blow up Confederate Fort Fisher at Wilmington, N. C. with a boat-load of explosives wouldn’t work.

In June, 1863, a powder magazine in Fort Lyon, defenses of Washington, exploded.  It contained about 28,000 pounds of powder. The destructive action was confined principally to the portion of the work immediately above the mine.  The parapets of the work, although but some eighty feet distant, were uninjured.  The men in the bomb-proof, not more than seventy-five feet from the explosion, were unharmed.  A house 350 yards from the explosion, although considerably shaken, was not destroyed.

[OR Series 1 Vol. 42 Part 1 Chapter LIV page 992]

In the second recital, Gen. Richard Delafield, Chief Engineer, U. S. Army provides even more detail on why the plan wouldn’t work.

Explosion of the magazine at Fort Lyon of the defenses of Washington, on the 9th of June, 1863.  The floor of this magazine was nine feet below the parade of the fort.  The space for powder was sixty- four by seven by seven [feet] covered on top with logs of fifteen inches square by eighteen feet long, and above them eight feet of earth (in thickness).  The amount of powder in the magazine was 17,500 pounds in barrels, besides which there was ammunition prepared for 900 cartridges for 22-pounders, 750 cartridges for 24-pounders, and 500 cartridges for 30-pounder Parrott guns, and about 200 rounds for field pieces.  The earth over and on top of the magazine was scattered in every direction, principally upwards.  It fell in considerable quantities at a distance of 400 to 500 yards. Other portions of earth were thrown to the right and left, and deposited immediately alongside the outline of the magazine.  The logs on top of the powder room were thrown in every direction.  Some pieces were thrown to a great distance; in one case 600 yards.  The breadth of the cavity in the earth formed by the explosion was about forty-five on top.  The explosion did not affect the other earthwork of the fort to any material extent, although it surrounded the magazine on three sides, and not more than eighty feet from the magazine, rising several feet above it.  One gun on the rampart was thrown (rolled) into battery and tipped forward, with its muzzle resting on the parapet.  The loaded shells in the magazine were thrown to various distances; in one case as far as 2,500 yards.  The wooden buildings and tents used as officers quarters, placed near the magazine, were entirely destroyed.  At the time of the explosion most of the garrison were in the bomb-proof, which opens on the front opposite the magazine and about seventy-five feet from it. All the officers and men therein escaped uninjured.  At a house 350 yards from the magazine the glass of the windows was blown violently in and the doors out.  The walls were started out and toward the magazine in one case more than an inch while the whole house was settled unevenly on its foundation.  Several persons were lifted up and thrown to some distance in one instance about 150 yards escaping with only slight bruises, while others sustained scarcely a mark on their bodies.

[OR Series 1 Vol. 42 Part 3 Chapter LIV page 642]

Finally, a magazine explodes with more horrific results.  The exploding ship plan didn’t work.  A second expedition succeeded in capturing Fort Fisher.  In the melee following the fort’s occupation, an interior magazine exploded, killing many members of a detachment bivouacked nearby.

I regret to report that shortly after sunrise on the 16th instant, the day following the assault, the magazine of reserve ammunition in the fort exploded, killing and wounding about 130 men.  The cause of this explosion has not yet been ascertained.  General Ames had caused guards to be placed over the magazines, and had taken precautions to prevent accidents.  A board of officers has been appointed to investigate and report upon the matter.

Report of Maj. Gen. Terry, commanding [OR Series 1 Vol. 46 Part 1 Chapter LVIII page 401]

FINDINGS.  After mature deliberation upon the foregoing evidence the court finds that the following are the main facts, viz:

I. Immediately after the capture of the fort General Ames gave orders to Lieut. Col. Samuel M. Zent, Thirteenth Indiana Volunteers, through Capt. George W. Huckins, Fourth New Hampshire Volunteers, acting assistant adjutant-general, Third Brigade, Second Division, to place guards on all the magazines and bombproofs.

II. Lieutenant-Colonel Zent commenced on the northwest corner of the fort next the river, following the traverses round, and placed guards on thirty-one entrances under the traverses.  The main magazine which afterward exploded, being in the rear of the traverses, escaped his notice, and subsequently had no guards from his regiment or any other.

III. That soldiers, sailors, and marines were running about with lights in the fort, entering bombproofs with these lights, intoxicated and discharging firearms.

IV. That persons were seen with lights searching for plunder in the main magazine some ten or fifteen minutes previous to the explosion.  The court do not attach any importance to the report that a magnetic wire connected this work with some work on the opposite side of the Cape Fear River.

OPINION.  The opinion of the court, therefore, is that the explosion was the result of carelessness on the part of persons to them unknown.

Col. H. L. Scott, Military Dictionary, Comprising Technical Definitions, Information of Raising and Keeping Troops, Actual Service, Including Makeshifts and Improved Materiel and Law, Government, Regulation, and Administration Relating to Land Forces will be cited as [Scott, Military Dictionary]

D. H. Mahan, A Treatise on Field Fortifications, Containing Instructions on the Methods of Laying Out, Constructing, Defending, and Attacking Intrenchments, with the General Outlines Also of the Arrangement, the Attack, and Defence of Permanent Fortifications will be cited as [Mahan, Treatise on Field Fortifications]

Q. A. Gillmore, Engineer and Artillery Operations Against the Defences of Charleston Harbor in 1863; Comprising the Ascent upon Morris Island, the Demolition of Fort Sumter, the Reduction of Forts Wagner and Gregg with Observations on Heavy Ordnance, Fortifications, Etc. will be cited as [Gillmore, Charleston Operations]

Capt. J. C. Duane, Manual for Engineer Troops will be cited as [Duane, Manual for Engineer Troops]

Hurdle

This revetment is made by driving poles … , and then forming a wickerwork, by interlacing twigs between them in a similar manner to basket work.

[Mahan, Treatise on Field Fortifications, page 39]

Gabions

Cylindrical baskets of various dimensions, open at both ends …

[Scott, Military Dictionary, page 320]

Fascines

… a bundle of twigs closely bound up.  There are two sizes of fascines; one size is nine inches in diameter, and about ten feet long; the other, which is generally termed a soucisson, is twelve inches in diameter and twenty feet long; it is chiefly used for the revetments of batteries.

[Mahan, Treatise on Field Fortifications, pages 37 - 38]

FASCINES are long cylindrical fagots of brushwood, and when designed for supporting the earth of extensive epaulements, are called saucissons, and are about 18 feet long, and ten inches thick; those for the revetment of the parapets of batteries are eight or ten feet long; those for covering wet or marshy ground from 6 to 9 feet long.

[Scott, Military Dictionary, page 283]

FASCINES are a superior kind of fagot, which being built in courses, with a moderate slope, and secured by pickets driven into an earthen parapet, form a revetment useful in field-works.

A Fascine, when the term is used without further specification, implies one about eighteen feet long and nine inches in diameter, such as is used in reveting batteries, &c., and which can be cut to any shorter length, as may be required, during the execution of the field-work in which it is used.  To make fascines thicker than the above dimension would be a waste of materials.

Trench Fascines, six feet long, are used for crowning a line of gabions in a sap.  These are formed by merely sawing the
common long fascine, or Battery Fascine, into three parts.  In like manner, nine-feet fascines, which are useful for covering blinded galleries, and for other purposes, are formed by sawing the common long fascine into two equal parts.

[Duane, Manual for Engineer Troops, page 55]

Rods, Withes or Gad, Pickets

A great number of fascines, gabions and pickets, are indispensable in a siege, and are often necessary in field-works.  For this purpose, brushwood, not exceeding from one and a half to two inches in diameter at the butt end, is most suitable.

The thicker pieces are usually called poles.  The smaller ones are called rods.

When brushwood is not to be had, branches of trees may be used for the same purpose : and the pickets in particular may always be split out of large timber.

[Duane, Manual for Engineer Troops, page 53]

Scott, Mahan and Duane don’t formally define withe or gad.  The two terms are frequently stated “withe or gad”, or something similar,to stress their synonymous use.

Withes or gads are the thin branches from bushes or trees interwoven to form the sides of hurdle and gabions and used in lieu of wire or cord to bind fascines together.

Scott does define “Picket” but we prefer our own wording.  A picket, as used in field fortifications, is simply a stake or post.  The term is used:

• To denote posts used in marking out the line of a field fortification [tracing]
• The framework of gabions and hurdle – withe or gad are interwoven around pickets to make a solid shape
• To describe a stake driven through a gabion or fascine to hold it in place on a parapet or cheeks of an embrasure

The terms “rod”, “withe” or “gad” and “picket” are used interchangeably.  It is usually clear from context whether the author means a post, a stake or a withe.

Methods for Weaving Hurdle and Gabions – Randing, Slueing, Pairing, Waling

In working with a single rod, which is called randing, an odd number of pickets must always be used.  The rod is alternately passed round one picket, and within the next, … commencing at the bottom …

Randing

Sometimes two or three rods are worked round together, precisely in the manner above described, and still using an odd number of pickets.  This is called slueing.

Slueing

… randing … and slueing … are both very weak, especially the latter; so that the strength of baskets made in this manner, depends entirely upon the top and bottom, which are always finished with greater care.

Working with two rods together, when braided or plaited, is called pairing.  In this case, the two rods are separated by one picket.  That which is to the rear is passed over the other rod, round one picket, and within the next.  The second rod, which is now to the rear, is passed over the first rod, and also round one picket, and within the next.  Thus the two rods cross each other alternately, over and under, …  This is the method usually practised in our service.

Pairing

In this, and in all the succeeding methods, it is of no consequence whether the number of pickets be odd or even.

Working with more rods than two is called waling.  In waling with three rods, they are first placed with the butts inward, and tips outward, each being separated by one picket, as in the annexed figure.  Then the first rod, which is to the rear, is passed over the other two rods, round two pickets and within one.  The second rod, which will then be to the rear, is also passed over the other two rods, round two pickets, and within one.  The third rod is next treated in the same manner.  Hence each rod will alternately come to the front in its turn, and they will always be separated from each other by one picket, … and thus in winding spirally round the pickets, the rods will be braided into the form of a three-stranded rope.

Waling

Basket-makers sometimes wale also with four or five rods, in a manner which I forbear to describe, as it is not applicable
to military purposes.

In passing a rod from the outside round the inside of any picket, and out again, the basket-maker does not move it all round by the top, in the way that an inexperienced person would naturally do.

Holding the rod in his left hand, with the tip pointing upward, he passes the fore-finger and thumb of his right hand into the inside … , between … two pickets, through which the end is to come out, after making the required turn, and with these bent backward, he grasps the middle of the rod, and pulls it out with a jerk, between the said pickets.

In circular waling, the rods should always pass round more pickets outside than inside.  In straight work, with the same number of rods, this is not necessary.  Because it is desirable that the inside of a gabion, or basket, shall be as nearly circular as possible.  But if several pickets be passed inside by each rod, the interior outline will assume the form of a small polygon.

When the rods for basket-work, or for withes, are to be used any length of time after they have been cut, they must previously be steeped in water to restore their flexibility.  It has also been recommended to heat green withes over a fire, before twisting them.

The best method for a young officer to learn waling, is to provide some wires as pickets, which he may fix on a large pincushion, using pieces of the small round cord called bobbin, as a substitute for the rods.  In this way very neat models of gabions may be made.

[Duane, Manual for Engineer Troops, pages 68 -71]

We have italicized Duane’s footnotes and raised them into the text.  All italics and emphasis added.

At West Point, cadets were taught to build hurdle, gabions and fascines during the annual “encampment”.  We think they used actual materials rather than being issued wire and pincushions.

Building Hurdle Revetment

The poles should be nine inches apart, their diameter about one-and-a-half inches.  They should be secured to the parapet by long withes and anchoring pickets.  The top twigs should be bound together by withes.

[Mahan, Treatise on Field Fortifications, page 39]

Hurdles are the common coarse wicker hurdles made for farming, and other purposes, usually 3 or 4 feet high and 6 to 9 feet long.  They are useful in temporary works, to retain earth at a steep slope, for ‘ a short time. When thus used, they should be secured by anchoring pickets.  Hurdles are moreover useful, to form a dry footing in trenches, during wet weather; in the passage of wet ditches, and for many similar purposes.

[Scott, Military Dictionary, page 508]

Hurdles consist of strong wicker-work, of a rectangular form, and as they may occasionally be useful in a siege, the
mode of making them shall be described.

The best size for military purposes is six feet long, and two feet nine inches high.  … generally speaking, the rods for hurdles should not be much less than an inch in diameter.

An even number of pickets must always be used; and I consider ten a good proportion for a six-feet hurdle, although the woodmen in this neighborhood generally employ only eight for a hurdle of that length.  The hurdles made by the Kentish woodmen are either eight feet long, with ten pickets, or six feet long, with eight pickets, and are usually three feet high.

In preparing to make a hurdle, it is necessary to describe an arc of a circle on the ground, with a radius of about eight feet, making the length of the arc six feet.  This space must be divided into nine equal parts.  A picket is then driven into the ground at each end of it, and others into every intermediate point of division, making ten in all.  The woodmen assert that hurdles intended to be straight must always be made curved in the first instance, as above directed, in order to prevent them from being crooked when pulled out of the ground, which they say that those made in a straight line invariably become.

Create tension ~ stability when straightened by building hurdle in an arc

The following method has been advantageously employed in constructing hurdles, viz. : a stick about seven feet long and five inches in diameter is notched at intervals, corresponding with the spaces between the hurdle stakes.  This stick is laid on the ground, and the stakes driven opposite each notch; it is then raised horizontally about eighteen inches, and the stakes lashed firmly into the notches, and are thus retained in place, whilst the upper half is wattled.  The hurdle is then reversed, the stick removed and the remaining half finished. 

Then the watling is begun, … in a continued line; and therefore when you come to one of the extreme pickets at either end, you must twist part of your rod like a withe, and bend it round the picket, after which you must work in the contrary direction.

In commencing a hurdle, the men work from the bottom upward, … the first rod is not pressed down close to the ground, excepting in the centre.  Both its ends are raised about nine inches above the ground, and there bent round the extreme pickets by twisting.  Thus the first rods used form an arc of a circle, concave on the upper side.  The second and third rods are bent round the extreme pickets, as close to the ground as possible, at each end of the hurdle, but in the centre they rise higher than the first rods used; and thus the first three or four rods, or rather courses of rods, composing the web of the hurdle, are interlaced in such a manner, by crossing each other toward the centre, as to prevent the separation of that part of the web from the pickets.

For strength, start and finish first two rows half way up, work to bottom center

The ends of the rods are kept in their places, by pressing against a picket, which jams them, and they are cut off about an inch in rear of it.  It is not good workmanship to commence or finish with a rod, by cutting it off, in this manner, close to either of the extreme pickets, as the twisted joint formed by bending the middle of a rod round those pickets, evidently gives greater firmness to the work.

After having commenced as described, the remainder of the web is worked up in parallel horizontal courses, until it
reaches the top of the pickets; and at this part one or two of the uppermost rods, after being twisted round the extreme
pickets, are passed diagonally downward in an oblique direction, toward the centre of the hurdle, passing through
and between one or two of the pickets.  This arrangement, which is also sometimes adopted about half-way up, as well
as at the top, prevents the upper part of the web from separating from the pickets.

In making hurdles for civil purposes, it is usual to work by randing, or with single rods only, for the thick brushwood
generally used in this process is so stiff, that it requires an effort to separate it from the pickets. But as military hurdles would be exposed to greater strains than those used in husbandry, it is better to pair the rods in making them, which may either be done throughout the whole of the web, from the bottom upward, or at least for several courses at the bottom, middle, and top; for this undoubtedly gives greater firmness to the work.  But the precautions before described for interlacing the lowest, and finishing the uppermost courses of the web, render it unnecessary to use vertical withes for binding it, ….

The men and tools …  with … bill-hooks and knives, …[in] a line ten feet long.  The probable time for making a six-feet hurdle would be about three hours ; I do not speak with certainty, having made very few; and it weighs about fifty pounds when the wood is dry.

Formerly a two-edged bill-hook was used in the service, calculated to act both as a hand-hatchet and bill, or to chop as well as cut.  Recently this complex and loss efficient instrument has been abolished, and a billhookof the Kentish pattern, a large curved knife, with the edge on the concave side, has been adopted in lieu of it.  In making hurdles, woodmen sometimes use a block-bill for capping pickets, which has a straight edge, with a small hook at the back; but, by a little management, the common bill will chop as well as cut, and it is not worth while to use two tools for military purposes. [Duane,Manual for Engineer Troops, page 53]  For a picture of a Kentish bill-hook, see our “Tools of the Trade” article.

[Duane, Manual for Engineer Troops, pages 80 - 83]

We have italicized Duane’s footnotes and raised them into the text.  All italics and emphasis added.

Building Gabions

The gabion is a round basket of a cylindrical form, open at each end, its height is usually two feet nine inches, and diameter two feet.

To form a gabion, a directing circle is made of two hoops, the difference between their radii being such, that, when placed concentrically, there shall be about one-and three-quarter inches between them.  They are kept in this position by placing
small blocks of wood between them, to which they are tied with packthread.

The directing circle is laid on the ground, and seven or nine pickets, about one inch in diameter and three feet long, are driven into the ground between the hoops, at equal distances apart; the directing circle is then slipped up midway from the bottom, and confined in that position.

Twigs half an inch in diameter, and as long as they can be procured, are wattled between the pickets, like ordinary basket work; when finished within about one-and-a-half inches of the top, the gabion is placed with the other end up, the  directing circle is taken off, and the gabion is completed within the same distance from the other extremities of the pickets.

The wicker work at the two ends is secured by several withes, and the ends of the pickets being brought to a point, the gabion is ready for use.

[Mahan, Treatise on Field Fortifications, pages 39 - 40]

Gabions are stout, rough, cylindrical baskets, open at top and bottom; they are made of various dimensions according to their intended use.  Those for revetting the interior slopes of parapets are usually 3 feet high and 2 feet in diameter; strongly and somewhat coarsely made.  Those used in sapping (called sap gabions) have about the same dimensions,
but are carefully finished.

To construct a gabion, a circle of 22 inches diameter must be traced on a clean, hard, level piece of ground, each quarter of this circle is then divided into four or five equal parts, and small holes made at the points of division, to receive straight uprights of 3 feet in length, around which the withes are interwoven.

Gabions may be made with one, two, or three rods woven together about the uprights; when two rods are woven together, the work is called pairing ; when three, waling. The last gives the strongest gabions.  Each rod passes outside two, and inside one, upright, and the three are twisted together like a rope.

[Scott, Military Dictionary, page 507]

For many years past we have made all our gabions of the same size, namely, two feet in exterior diameter, and two
feet nine inches high in the web, but averaging three feet in height when used for the revetment of a trench or fieldwork,
in consequence of the projecting ends of the pickets.  Hence when the term GABION is used, without further specification,
it implies one of the above dimensions, and no other.

To make larger gabions than the above would be useless, for we ascertained by repeated experiments, that two-feet gabions formed as strong and durable a revetment as those of greater diameter; which result was the more conclusive,
having been contrary to our expectations; and we also found that there was no advantage in using smaller ones.

At one time we used not only two-feet gabions, as above described, but also twenty-one inch gabions.  The latter, being employed exclusively for the regular sap, were called sap-gabions, to distinguish them.

The batteries being of greater importance than most of the other works of a siege, it is proper to finish them in the most substantial manner, and therefore we use the strongest and heaviest gabions, made of the thickest brushwood, for this purpose.  In other respects there is no difference between Battery- Gabions and Trench- Gabions.

The men employed in making gabions may be divided into squads of three men each, of whom one prepares pickets, rods and withes, whilst the others level the ground, and afterward work at the gabion.  In some cases two men may suffice.  One private has charge of each squad, under the non-commissioned officers, who superintend several.

When a party of men are sent to make gabions, pickaxes and shovels should be taken to the ground, if necessary.

The footnote indicates the handsaw may be dispensed with if the crew is adept with the bill-hook.

In making gabions, wooden circles are sometimes used, consisting of plank ledged together so as to form a circle like the head of a cask.  Notches are cut on the circumference to receive the stakes.  The circle is laid on the ground, the stakes driven around it and in the notches, the circle raised a foot, and the stakes bound firmly into the notches by means of a rope and rack-stick.

The gabion is then wattled above the circle, and withed, turned over the circle removed, and the remaining portion wattled.  I am informed that this facilitates the operation, and saves time, when inexperienced men are employed; but I conceive that no extra implements of this description that can possibly be dispensed with, ought to be used on service.

When wooden bottoms are used in gabion making, the proportion is one per squad.

METHOD OF MAKING LIGHT GABIONS
The pickets must be from three feet four to three feet six inches long; and their proper thickness is from five-eighths to seven-eighths of an inch.

The rods for the web should be from five-sixteenths or three-eighths, to three-quarters of an inch in diameter.

Those for the withes should be a little thicker, and the most perfect that can be selected.

The number of pickets used in working with brushwood of the above description should not be less than fourteen.

Gabions are usually made by driving the pickets into the ground, and therefore in hard or rocky soil small pits about two and a half feet in diameter, and nine inches deep, must be dug at proper intervals, and filled with loose earth, excluding stones and large gravel.

A circle of the proper diameter must then be traced, with a piece of string made fast to two short pickets, one fixed into the ground as a centre, the other moving round to mark the circumference.  The diameter of the circle thus traced should be one inch less than that of the proposed gabion.  Hence the proper radius for a two-feet gabion is eleven and a half  inches.

When this is done, the circumference must be divided into as many equal parts as there are pickets to be used in the
proposed gabion.  When twelve pickets are to be used, the best way is to divide it first into four equal parts, and afterward
to subdivide these portions into three each.  A small piece of stick may be used as a measure.

All the pickets must next be driven, so as to touch the internal circumference, as shown in the annexed figure, and it is
proper to place them alternately with the large and small ends upward.

The rods prepared for the web must be entirely stripped of leaves and twigs; no part of any one single rod being used
double, although in joining a new rod to the tip of one that is coming to an end, these two may be laid together for a
few inches.

The most approved method of forming the web of light gabions, is by waling with three rods, as described in the foregoing observations; but it will be best not to place all the butts, or thick ends, the same way.

If the stuff be larger than usual, pairing with two rods may be allowed, but this method must be confined to the body of the gabion only.

Five or six inches of the bottom, and as much of the top, must always be waled with three rods.

Very thin short rods should not, in any case, be used at the top or bottom of a gabion ; for, unless these portions of the work are finished with more than usual care, they are liable to separate from the remainder of the web, whilst the gabions are carried or thrown about.  These portions may be formed of twisted withes, instead of common rods.

Twisted withes, braided or plaited, are used in preference to common rods, for all very open wicker-work, as they are less liable to separate from, or slip up and down the pickets with which they are connected.  In gabions this is not absolutely necessary.

Iron wire may bo substituted for withes in the construction of fascines and gabions.  This material is superior both in strength and durability to the withe.  When used, a pair of pincers must be added to the list of tools for each party.  The wire should be annealed, by heating it red-hot.

In making the gabion, the web must continually be pressed down with the foot or hand, or beat with a stout picket; and the greatest care must be taken to preserve the proper diameter, for which purpose a couple of rods may be cut as gauges, which may be placed transversely across the finished part and inside of it, pressing against two opposite pairs of pickets.

When the web is completed to the proper height of two feet nine inches, it must be bound from top to bottom, with withes, previously well twisted, in four distinct places, and these should be applied, so as to secure the ends of the extreme rods, in preference to the middle of them.

The centre of the withe being laid over the top of the web, the ends are passed through it, in contrary directions, a few
inches from the top; near to each other, but not between the same two rods.  Two men haul upon them, till they are quite taut.  They then pass them again through the web, a few inches lower down, in contrary directions, and haul taut a second time; and thus they proceed by double stitches, as they may be called, like those of shoemakers, until the ends of the  withe arrive at the middle of the web.

The gabion, being thus secured by four withes from the top downward, disposed at equal distances apart, is pulled out of the ground, and turned upside down; and an equal number of withes are used, to bind the remaining part of the web, in the same manner, so that the two sets of withes used shall meet, or cross each other, about the centre of the gabion.

The ends must be neatly secured, but in what manner is of little consequence.

The stitches of these bands should be rather close, but not so as to embrace fewer than two spirals, of the original waling of the web.

Before the gabion is pulled out of the ground, the tops of all the pickets must be cut off about an inch above the web.  This is usually done by a handsaw, but the expert woodman cuts off the heads of pickets by his bill-hook, introducing a stout stake between two of the pickets, which he uses as a movable chopping block, in striking at one of the two.

After the gabion is turned upside down, the points which originally stood in the ground may also be cut off, according
to the same rule, if judged necessary; we always leave them, which appears to be rather an advantage than otherwise.

METHOD OF MAKING GABIONS OF VERY SMALL BRUSHWOOD
Lighter gabions than those described in the preceding article are not to be recommended, otherwise than as a matter of necessity on service; or of economy, where very small brushwood is often used, in order that nothing may be wasted.

For example, when none of the brushwood runs larger than about five-eighths or three-quarters of an inch, the pickets will not of course exceed from one-half to three-quarters of an inch, and the tods may vary from one-quarter of an inch, or even less, to about one-half, or at the utmost, five eighths of an inch.

In this case, the number of pickets used must be increased from fourteen to sixteen, or even twenty, using the greatest
number to the smallest brushwood; and the making of gabions with such very light materials, requires more than usual dexterity and attention.

In other respects the method is the same as in making the common gabion before described.

In gabions made of very small brushwood, the ends of the pickets should always be cut off, after drawing them out of the ground; otherwise they are liable to break.  This is  done by the gabion knife, not by the saw or bill-hook.

After finishing one gabion, and drawing it out of the ground, the same picket holes will answer for commencing a second gabion, without describing a new circle.

METHOD OF MAKING GABIONS OF THICK BRUSHWOOD
Sometimes thicker brushwood than usual must be employed for making gabions, as a matter of necessity.  Sometimes
stronger gabions may be desired for some special purpose, such as reveting the embrasures of a battery, or for the interior of a field powder-magazine, in which case the thickest parts of the brushwood are selected.

The pickets for strong two-feet gabions, need not exceed from seven-eighths to one inch, or, at the utmost, one and a quarter inch in extreme thickness.  The rods for the web should not be less than one-half or five-eighths of an inch, and need not exceed one inch in thickness, the best being selected for the withes.

On account of the greater strength of the brushwood used, the pickets may be reduced to eight or ten for gabions of the above diameter; and the whole of the web may be formed, by pairing with two rods only.

The proper number of pickets for gabions made of strong brushwood, is in the proportion of one picket to every two and a half or three inches of diameter.

In other respects, the same method is followed, as in working with smaller brushwood.

The time required for making gabions, by common military working parties, after some days’ previous practice, may safely be estimated as follows, observing that it increases in direct proportion to the number of pickets and smallness of
the rods used.

Three men will finish a gabion, with eight or ten pickets, and of large brushwood, in two hours; they will finish a common gabion, of fourteen pickets, and of smaller brushwood, in three hours; but they cannot finish properly a very light gabion, of from sixteen to twenty pickets, and of the smallest brushwood that can be used, in less than from four to five hours.

The average weight of gabions may be estimated at thirty-six pounds, and they scarcely much exceed forty pounds, even when made of large brushwood.

[Duane, Manual for Engineer Troops, pages 67 - 76]

We have italicized Duane’s footnotes and raised them into the text.  All italics and emphasis added.

For special circumstances where extra-tough material was needed, e. g., the cheeks of embrasures, engineers made gabions of iron.

METHOD OF MAKING IRON GABIONS
Describe a circle two feet in diameter on a wooden platform.  Divide the circumference into six or eight equal parts (half the number of stakes to be used in the gabion); at each of these points insert wooden pins about five inches long.

Wrap the hoop iron tightly around the pins, thus forming a polygonal hoop.  The point where this hoop is to be riveted must be marked before it is removed from the form, so that all the hoops may be of the same size.

The hoop is then punched and riveted.

As the iron used is usually one inch wide, thirty-three of these hoops will be required for a gabion.

The stakes are usually made from pine plank one inch thick; their cross section being a triangle, with three or four inches base and one inch altitude.  This is the best form, although round stakes may be used.

To set up the gabion, place a hoop on the ground, and a second directly over it, the first as represented by the dotted, the second by the full lines in the figure.

Insert a stake in each of the triangular spaces, then place the remaining hoops alternately over the first and second.  Drive nails in four of
the stakes over the exterior hoops to keep them from coming off.

This gabion is much stronger and more durable than those made of brushwood, and is peculiarly adapted to the construction of the cheeks
of embrasures, as it is not injured by the blast of the piece.

CORRUGATED IRON GABIONS
For this purpose, the corrugated sheet should be six feet long, thirty-three inches wide, and of iron weighing three quarters of a pound to the square foot.

The corrugations running transversely, the sheet is easily bent into a cylindrical form, in which it is retained by two clamps, the holes for which are punched near the corners of the sheet.

The chief advantage claimed for the corrugated over the hoop gabion is, the readiness with which it can be put together on the field.  It is also rather more portable, and stakes are dispensed with; but it is inferior to the latter in stiffness.

[Duane, Manual for Engineer Troops, pages 76 - 78]

Details of building iron gabions during the siege of Fort Wagner:

[Gillmore, Charleston Operations, pages 345 - 246]

Building Fascines

To make a fascine, straight twigs are selected, between the thickness of the little finger and thumb, the longer the better; they should be stripped of the smaller twigs.

A machine, termed a fascine horse, is put up, by driving two stout poles obliquely into the ground about two feet, so as to
cross each other about two feet above the ground, where they are firmly tied together; as many of these supports as may be required are put up in a straight line, about eighteen inches apart; this forms the horse, on which the twigs are laid to be bound together.

Another machine, termed a fascine choker, is formed of two stout levers about five feet long, connected near their extremities by a chain or strong cord, which should be long enough to pass once round the fascine, and be drawn tight by means of the levers.

The twigs are laid on the horse, with their large and small ends alternating; the choker is applied to bring them together; and they are bound by withes, or gads, made of tough twigs, properly prepared by untwisting the fibres over a blaze, so as to render them pliant; or else stout rope yarn may be substituted for them.

The gads are placed twelve inches apart, and every third or fourth one should be made with an end about three or four feet long, having a loop at the extremity to receive a picket through it; this picket is termed an anchoring picket, its object being to secure the fascine firmly to the parapet.

[Mahan, Treatise on Field Fortifications, page 38]

Fascines are strong, close, regular fagots, carefully and compactly made, generally of green brushwood.  They should be straight, cylindrical, and pliant; bound round with good thick, unbroken gads or withes, of pliant wood, at equal distances, the knots well tied, and all in one line; no variation in girth exceeding 1 inch to be allowed.

Fascines are of several kinds and various dimensions, according to the purposes for which they are intended.  The most common are the long fascines or saucissons, 18 feet long, 9 inches in diameter, about 140 lbs. in weight; such a fascine can be made by five men in one hour, including the cutting of the wood when at hand.

Water fascines, 18 inches in diameter, 6 to 9 feet long.  Trench fascines, 4 or 5 feet long, 6 inches in diameter.  Sap fagots, 3 feet long, 9 inches in diameter, having a sharp-pointed stake, passed longitudinally through the centre, and projecting a foot or so beyond the extremity of the fascine.

To make good fascines requires considerable practice and much care and attention.  The process is this: Stakes are driven into the ground, obliquely, in pairs, so that the stakes in each pair cross at the same height above the ground about 3 feet, where they are firmly bound together, forming a row of trestles each in shape like the letter X.

These trestles should be placed about 4 feet apart when the brushwood is good; closer together when it is bad.  Thus 5 trestles at least will be requisite to prepare 18-feet fascines.

A choker must now be prepared.  This is made by fastening, by an iron ring, each extremity of a chain about 4 feet long, to an ash stake.

Each stake is 4 feet long, and the point where the chain is fastened is about 18 inches from the thicker end. Two small rings are attached to the chain 28 1/2  inches apart, (equal to the circumference of the fascine, and equidistant from its middle point.

In choking the fascine, the middle of the chain is placed under it, and the ends brought over and crossed.  Two men, one on each side, then bearing on the longer arms of the levers tighten the chain, and compress the fascine to the proper dimensions, that is, until the rings on the chain meet.

A third man now binds the fascine as close as possible to the choker, with a strong gad, or with stout spun yarn, when the choker may be removed and the operation repeated at the proper intervals, generally 18 inches.

For withes or gads to bind fascines, very straight rods must be selected; they should be 5 feet long, not thicker at the thickest part than the thumb, nor thinner at the thinnest than the little finger.  To prepare them for use, place the thick end under the foot, and twist the rod from the top downwards, by which the rod will become flexible and capable of being securely knotted without fracture.

The knot to be formed in fastening the gad round the fascine is shown in Fig. 180.

To make the fascine, the brushwood is laid in the trestles, the longest and straightest rods being kept round the outside, the inferior material in the middle.

The proper quantity of brushwood having been thus carefully arranged, the choker is applied near the extremity of the fascine, and subsequently at intervals of 18 inches as already mentioned.

The ends and exterior are now neatly trimmed, by the hand saw and billhook, and the fascine is complete.

When good gads or withes cannot be procured, stout, well-tarred spun-yarn may be substituted for them.

With fascines are prepared bundles of stakes, called fascine pickets, in the proportion of six to each fascine; they should  be 4 feet long, 1/2 inch in diameter, and be cut to triangular points.

[Scott, Military Dictionary, pages 504 - 506]

Fascines are made in a cradle composed of a certain number of trestles, placed at intervals not exceeding four
feet apart.

Each trestle consists of a couple of stakes about six and a half feet long, and not less than from two and a half to three inches in diameter, driven obliquely into the ground, touching each other, and crossing at right angles, or nearly so, in the form of a St. Andrew’s cross.  The upper part of the cross should stand at the perpendicular height of about two feet six
inches above the ground, with the ends of the stakes projecting obliquely about two feet beyond it, …

At the centre of the cross, the trestle may be secured by a lashing six feet long, consisting of a piece of spun-yarn
or tarred line, of the size of tracing line, or a very little larger.  This is done by applying the middle of the lashing to the two stakes, and passing the ends horizontally round both until some three or four turns are taken.  The ends are then
crossed vertically round the centre of those turns, in the space between the two stakes, and hauled taut; and after taking two or three turns in this new direction, … the ends are tied together with a reef knot.

The turns last taken are technically termed flapping turns, and by straining the first part of the lashing, keep every thing tight.  A withe or twisted rod may answer the same purpose when lashings cannot be procured.

When one trestle is thus fixed, another is always placed at the distance of sixteen feet from it.  The intermediate trestles, which may be three in number when the brushwood is good, making five in all, are then placed at equal intervals of four feet apart, between these two.  When the brushwood is bad, that interval will be too great, and therefore six or even seven trestles may be used instead of five.

The head of the squad directs the placing of the trestles, assisted by two men of his party, whilst the others collect brush-wood.

After the first two trestles are properly fixed, he aligns the others by the eye, looking along the upper side of each stake, on the same principle as in profiling.

At this establishment [West Point] we sometimes use stakes of fir, of regular scantling, about two and a quarter by three inches square, shod at bottom and hooped at top with iron, like small piles, and connecting each pair by an oak pin passing through holes cut for the purpose in the centre of the cross.  Although these make very good fascine trestles, one would scarcely recommend using them on service.

FASCINE MAKING DESCRIBED
When the trestles are fixed, straight rods and branches, not exceeding about one and three-quarter inches in diameter,
are laid over them, with their ends projecting about seventeen or eighteen inches on each side, beyond the extreme
trestles.

The leaves must be stripped off entirely, as well as the refuse ends of the thin branches.  When the branches grow out of the stem, with irregular or clumsy bondings, they should be first separated by the bill-hook, as all very crooked parts injure the fascine; but straight and flexible branches may be laid in along with the stem, cutting them half through or not, as may appear necessary.

The men piling the brushwood should endeavor to lay the stouter rods outside, and the smaller stuff near the heart of the
bundle.

When the cradle is nearly full of brushwood, it will be time to prove the diameter of the proposed fascine, in several places, which is done by the fascine choker; and more stuff is added in those parts which require it.

The fascine is then finished by binding it with withes prepared for the purpose.  This is done by four men, two of whom
choke, or compress the brushwood near the spot where the other two bind.

The first band is applied near the extreme end of the fascine, about six inches from the first trestle. The second is applied about fifteen and one-half inches from the first, and others are successively added at the same central intervals, until the whole number of thirteen bands are completed.

The fascine is then removed from the trestle, and the rough ends sawed off.  It is to be observed that these ends should be laid as regular as possible in piling the brushwood, and no more should be cut away than is necessary, although
the length of the finished fascine should, in this case, prove to exceed the standard of eighteen feet.

In regulating the central distance from band to band, the gauge-rod is used as a measure.

If the brushwood be very bad, or withes of the desirable length cannot be obtained, the intervals may be diminished to twelve inches, which will increase the number of bands to seventeen, and in this case a twelve-inch gauge must of course be used.

Strictly speaking, four men are sufficient for making a fascine, when all the materials are at hand, but the fifth may be usefully employed in preparing withes, which is the most difficult part of the work.

METHOD OF PREPARING AND USING THE WITHES
For Withes (or Gads as they are also called) to bind fascines, very straight rods must be selected, which when afterward
cut to the proper length of about five feet, should not be less than about three-eighths of an inch in diameter, nor greater, if possible, than about three-fourths or seven-eighths of an inch at the big end.  In choosing them, therefore, let no part be smaller than your little finger, or much thicker than your thumb.

All the small branches must be lopped off, not close to, or cutting in upon the stem, but so as to leave a small stump projecting about one-eighth of an inch above it; otherwise the rod will be liable to break at each knot.

In preparing them for use, you must put the thick end under your left foot, and twist the rod with your hands, from the top downward, with your right hand toward the end of the rod, which you will move in the same manner, nearly, as if working at a winch, so as to turn the rod in the direction technically called ” with the sun. “  “With the sun,” and “against the sun,” are in reference to the apparent motion of the sun, as observed by a man standing in the northern hemisphere and looking toward the south.

Great care must be taken to avoid making kinks in the wood, which unpractised persons are apt to do, as these
spoil the withe.

After the rod is well twisted at the small end, and moderately so downward, you will form a loop about nine inches
long, near the small end of it, by taking a half-hitch with the end of the rod round the body, or standing part of it, …

You will then give the loop a couple of twists in the contrary direction, so as to plait the double part of the rod, and form an eye, or smaller loop at the top of it, …

At the part where this eye is formed, the rod should not be less than half an inch in diameter.

Lastly, the end of the rod must be pointed, after which it will be ready for the use of the fascine makers.  In this state it should be at least four feet long, which, after preparing one or two, a man may easily judge of by the eye.

In binding the fascine, two men assist, standing on opposite sides.  They pass the withe under the brushwood, then
bring the ends together above it, and pass the big end of the rod through the eye.

One man sets his foot upon the eye, and forces it home, it being at this time some inches lower than the top of the fascine. At the same time he hauls upon the end of the rod, turning it with his hands, until the part within the eye is more  completely twisted, but, of course, in the same direction of the fibres as before.

He then hands over the end of the rod thus twisted to his comrade, who bends it back, so as to form a, new loop engaged within the former, like two links of a chain, after which he (the second man) passes the end of the rod from left to right, under the standing part on his own side, over it again, and then under it a second time; whilst the first man assists with the fid, in disengaging the standing part, which at this time is, of course, jammed close to the body of the fascine.

After the second turn, the superfluous part of the rod is cut off; and then the two ends appear exactly alike, excepting
that the thicker part has not got a half-hitch at the extremity of it, like the other part.

METHOD OF CHOKING A FASCINE
The instrument called a fascine-choker, consists of a stout chain, attached to a couple of ashen levers, each of which is
four feet long, and cut out of one and three-quarters by two inch scantling, the section of the wood being an oval.

The chain is four feet long, between the levers, which it embraces by means of a couple of iron sockets.  It is fixed at the
distance of eighteen inches from one end of each lever, from whence they taper to both ends.  There are two small rings
attached to the chain, one on each side of the centre, at the distance of twenty-eight and two-sevenths inches apart,which
corresponds with the circumference of a nine-inch fascine.

In choking the bundle of brushwood, which is done by two men standing on contrary sides of it, the centre of the chain is first brought under the brushwood, and then the ends of it, together with the levers, are brought over and crossed; the men handing over the opposite levers to each other, with the long ends uppermost.

The levers and chain will then … have made rather more than one complete turn round the fascine.  The small
rings … do not yet meet, as the chain is supposed to be slack.  The short ends of the levers press against the contrary sides of the fascine.

Commencing at this position, the two men press down the long ends of their respective levers, and thus by degrees tighten the chain, until the brushwood is choked, or compressed into as small a space as possible, when it assumes the form of a perfect circle, or nearly so.

At this period the long ends of the levers should be depressed below the horizontal line, and the two rings, which at first were several inches apart, ought to meet at the top of the fascine.  Hence, if fascines were made of different thicknesses, the length of the chain of the fascine-choker used, should vary according to the diameter of the proposed fascine.  Five and a half times the diameter is a good proportion.

As soon as each band is finished, the men employed in choking disengage their levers and chain, and commence at a
new place.

If any part of the fascine has been pinched in choking, it may be turned over when finished, and the bands or fascine beat with a picket, to render the latter quite cylindrical.

In making fascines, the officers and non-commissioned officers superintending, must be very strict, in regard to dimensions and neatness; more especially in seeing that the withes are properly selected, well twisted, particularly at the eyes, and in every respect made according to rule, for upon these, the strength of the fascine almost entirely depends.

When good withes cannot be had, spun-yarn may be used in lieu of them, which must be cut into lengths of six feet.  In binding with spun-yarn, the centre of the piece of rope is laid upon the fascine, and the ends are passed under, so as to make one complete round turn; they are then hauled taut, by the two binders pulling against each other; after which they are brought together at top, and crossed so as to form the first part of a reef-knot.

The two men again haul taut, by pulling in contrary directions, after which one man presses down the joint of the spun-yarn with his finger, until the other has taken the necessary turns, for completing the reef-knot.  Thus the band passes twice round the fascine, before the knot is tied.

If proper chokers are not to be had, a couple of stout stakes, and a rope doubled by splicing, or rather by tying the ends together, will answer the same purpose.  The length of the rope must be equal to that of the chain and sockets, in lieu of which it serves.  After the rope is passed round the fascine, and crossed, the ends of the levers are pushed through the bights of the rope, and the operation of choking is then performed in the usual manner.

TIME REQUIRED FOE MAKING FASCINES, WEIGHTS, ETC.

The men employed in making fascines must be divided into squads of five men each, besides which there must be spare men in the proportion of one to every three or four squads, to prepare pickets.  One private in each squad is appointed to direct, but not without taking his share of the labor.  One non-commissioned officer has the charge of several squads.

The size of the common handsaw is convenient, but its teeth are rather too large for sawing brushwood
expeditiously.  If regular six-feet rods cannot be issued to every squad, let a rod eight feet long, cut out of the brushwood, be used as a measure for each squad that is deficient.

Two lengths of this rod will mark the distance between the extreme trestles.  The fids of hard wood should be about nine inches long, one inch in diameter, and pointed at one end.  The gauges are pieces of wood about fifteen and a half inches long, also cut out of the brushwood.  Chopping blocks it is needless to describe; but if large timber is not to be had, stout stakes driven into the ground, and standing about two feet above the surface, will answer the purpose.  If a lower block be used, the man must work kneeling.

Every squad of five men may finish fascines at the rate of one in an hour, after a few days’ practice.

Expert men may make fascines much quicker when tasked, but it would not be prudent to calculate on making greater progress, with the common military working parties in a siege.

The average weight of an eighteen-feet fascine, is one and a quarter cwt, or one hundred and forty pounds, after the wood has been cut some weeks.

The men employed in cutting pickets must provide them in the proportion of six or seven to each fascine, and should
make them up in bundles of twenty-five.  They should not be less than three feet six inches long, including the points, but four feet is better.  A sharp triangular point is considered the best way of finishing the picket, and this form penetrates a stout fascine with great ease.  The top should also be pointed, but very obtusely, … for if it be cut perpendicularly across, so as to form a plane surface, the picket will be liable to split, in driving.

Contour the top of a picket to avoid splitting

All the branches must be cut off quite close to the stem.

Fascine pickets should not exceed one and three-quarter inches in diameter at the thick end, but from one and a quarter to one and a half inch is a better proportion.  After a little practice, a man’s eye is the best guide for judging of the proper thickness.  When the stuff much exceeds two inches in diameter, pickets must be formed by splitting it into two or more parts, according to its size.

After a few days’ practice, a man may cut and make up fascine pickets into bundles, at the rate of one bundle (or twenty-five pickets) in an hour.

A couple of withes, or of pieces of spun-yarn, must be used for binding each bundle.

The average weight of a bundle of well-sized pickets, three and a half feet long, is about thirty pounds, after the wood has been some weeks cut.

TRACING-FASCINES
The tracing-fascines, five or six feet long, recommended in all the elementary writers on the attack of fortresses, being of no use whatever, except to measure the task of each workman, in opening the trenches in a siege; and it being evident, that almost every other mode of effecting this measurement, that can be suggested, would be simpler than the above, the use of tracing-fascines has been abolished ; they were made four inches in diameter, in order to waste as little brushwood as possible.

COVERING-FASCINES
Covering-fascines are those made of stout picket stuff, not less than one inch thick, without any mixture of small brushwood.  They may be used in place of planks for the superstructure of wooden bridges; and may also be used, if no
stout planks or spars are to be had, for the roofs of field powder-magazines.  They maybe made of the usual diameter
of nine inches.  Their length will depend upon the special purpose for which they are intended.  The withes should be
particularly good.

A covering-fascine, made of willow, twelve feet long and nine inches diameter, was found by experiment to be equal to the calculated strength of a piece of Riga fir, about two inches and nine-tenths square.  Consequently covering-fascines, although strong enough to bear the weight of any military carriage or wagon, if supported by proper beams, not more
than four feet apart, are not quite so strong as common three-inch planks.  The strength of a common fascine of the same diameter, was about five-eighths of that of the covering-fascine.

SAP FAGOTS
A sap fagot is a short but very strong fascine, about three feet long, and nine inches in diameter, composed also of stout picket stuff; which may be used, instead of sandbags, for filling the interstices between the gabions, at the head of a sap.

One picket usually projects five or six inches from the end of the sap fagot, and is driven into the ground to keep it steady, when set upright, in which position it is always placed.

Sap fagots are also sometimes used for filling the gabions themselves, to hasten the progress of a sap, under peculiar* circumstances.

TRACING-PICKETS
These are short pickets eighteen inches long, and about one inch in diameter, which are useful in marking out the details of field-works.  When they are to be used in the dark, the bark should previously be stripped off.  They may be made rather more expeditiously than fascine pickets, and should be tied up in bundles of twenty-five each.  Every bundle weighs about eight pounds when the wood is dry.

We tried experiments with green willow cut a month before it was used, to ascertain the strength of fascine bands of different kinds, by applying progressive weights, until the withes broke.  Eyes formed according to rule, at a part of the rod not exceeding half an inch in diameter, required an average weight of more than four cwt. to break them; but in
some few instances, the standing part broke before the eye.  Under the supposition of such eyes being the weakest part, another method of forming a fascine band was suggested, in which the thick end of the rod was not passed through the eye, but round it, on the principle of what is called the midshipman’s hitch in knotting with ropes; but on trial the round turn thus taken with the thick end, unexpectedly proved to be the weakest part, and invariably broke under an average weight of two cwt. only.

DETAIL OF MEN FOR CUTTING BRUSHWOOD
When troops are ordered for this duty, it will be most convenient to tell them off in divisions of twenty-five men each. These must be subdivided into squads, in proportion to the number of non-commissioned officers present, each of whom will be responsible for the work of his own squad, but corporals, as rank and file, are not exempted from their share of personal labor, unless it should be considered that they may be more usefully employed in superintending.

The men must be drawn up in single rank, and in extended order, not less than three yards apart; and if there be not room for the whole of the divisions employed, to work in one line, they may either commence in several parallel lines, at  intervals of about thirty yards apart, or on different sides of the wood.

The brushwood must be made up into bundles, loosely bound together by withes; the size and weight of each to be such as a man can conveniently carry to the rear.  In wood that has attained the proper age, a bundle may contain
from twenty to forty rods.  The average weight of those made by military working parties will scarcely exceed forty pounds.

On commencing the work, all the men should cut; afterward a few should be told off to bind and carry.  After the first day’s work, the whole may be tasked to clear a certain extent of ground.

If the men have to march four miles to the wood, a task involving five hours’ labor on the spot, will probably be sufficient
for each relief or party of men.  If the wood should be nearer to the camp, their task may be increased.

[Duane, Manual for Engineer Troops, pages 54 - 66]

Gabions and fascines were designed to be used together when erecting revetments.  The idea is extremely astute – a strong, reliable, flexible building system made from materials found almost anywhere.  This article is getting too long, so we’ll pick up the narrative of how gabions and fascines were coupled in actual practice in another post.

Hurdle and sandbag revetment appear in more photos of Confederate fortifications than Union.  There is nothing we know that documents a preference for any one type by either side, it’s just an impression left after viewing hundreds of period photographs.

As fascine chokers were made in advance, the length of the chain or cord limited the diameter of fascines to the [approximately] standard 9 inch and 12 inch sizes.  Lengths were always meant to be adjusted to suit any particular situation.

Hurdle could be made in any reasonable height and length, adjustable to the circumstances.

Gabions seem to have been a standard size wherever and whenever they were built.

Let’s look at some real-life uses for the three types of revetments covered in this article.  First, hurdle:

Hurdle Revetment - Confederate Field Fortification

Perhaps the best-known photos of gabions and fascines are the series taken at Union Fort Sedgwick a few days after the move from the Petersburg lines.  Here is an infantry parapet from the set:

There’s a lot of information in this photo.  Until we finish the article covering how this revetment was actually built, it would be jumping the gun a bit to go into detail.  We’ll point out a couple of things which were covered in this article.

Let’s take a closer look at the fascines.  With plenty of alternatives readily available, no withes here.  The fascines are bound with cord.  The cords are all still tight, indicating a good knot on the parapet side.  A bit difficult to make out without the ability to zoom, but if you look at the section just this side of the rifle musket, you see one fascine laying nicely over nine gabions, or an 18-foot fascine.  At the magnification we were using in Photoshop, the gabions are about 260 pixels tall, the fascine about 70 pixels  in diameter.  Very close to four to one.  Assuming the gabions are the correct 36 inch height, the fascines would be nine inches, a reasonable expectation.

Now check out the gabions.  Note the “pairing” method used in the weave.  Note how uniform the construction – the builders had some practice by the time these were made.

Who actually built the literally tens of thousands of gabions and fascines used during the war?  In the ideal Civil War, it would have been the trained engineers.  They were far too few in number, however, to do more than supervise.  In every military jurisdiction, a cadre of infantry were trained, then put in charge of work crews detailed from infantry units.  At Petersburg, two Ninth Corps units, the 35th Massachusetts Volunteer Infantry and the 7th Rhode Island Volunteer Infantry, were assigned as the Corps engineer troops.  We have both of their excellent regimental histories.  From the regimental history of the 35th Massachusetts:

After the main lines were thus established, the regiment, for days in succession, was taken to the rear into the woods, and taught by the regulars to construct gabions, fascines, and other siege materials.  From the eighth to the twentieth of July the regiment averaged about one hundred and fifty gabions a day, and became very expert.

[History of the Thirty-Fifth Massachusetts Infantry, page 259]

The 7th Rhode Island regimental history, in diary form, 10th of July 1864:

The entire regiment is conducted to some woods in our rear and thee taught how to construct gabions.  These are made with green twigs so interwoven as to form wicker cylinders, and when filled with earth, constitute the chief support of the sides of heavy field fortifications.

July 14, 1864:

The army has settled down to unexpected quietude.  We still take to the woods to make gabions.  Each man is expected weave one a day.  The day’s product is brought to the camp in wagons.

[William P. Hopkins, The Seventh Regiment Rhode Island Volunteers in the Civil War 1862 - 1865, pages 196 - 197]

A detailed accounting of building materials from Gillmore’s report on the siege of Fort Wagner:

[Gillmore, Charleston Operations, page 245]

We’re going to wrap this up with a somewhat different account of a soldier’s experience with gabions, from the regimental history of the 4th Rhode Island Volunteer Infantry:

We have mentioned the fact of a large lot of gabions having been made by the Seventh Rhode Island.  An incident occurred to the writer and several comrades in connection with these gabions …

A great number of them had been made, and were piled up in an immense heap in the woods, about one and a half miles in our rear.  A guard of a corporal and three men from the regiment, were daily sent over to watch them, and keep them from being appropriated by other troops.  The writer with his three men, duly reached the place that day, and relieved the old guard there.

In the midst of the huge pile, an open space had been made, for the comfort and convenience of the guard, and was reached by a narrow entrance, or lane, from the outside.  In this space a large fire was built, to kep us warm, and enable us to cook our rations.

There being no special necessity of keeping awake all night, we fixed up a good fire of heavy logs and at about 10 o’clock turned in, and rolling ourselves in our blankets, were soon fast asleep.

Somewhere about midnight, a log laying across the fire burnt in two, and rolling down against the gabions, set them on fire.  Being composed of dry twigs and vines, they burned like tinder, and very soon the inside of our little chamber was all ablaze.

The crackling of the flames as they spread around the inclosure and leaped high in the air above the top of the huge pile, awoke us, and seizing those of our affects we could most easily reach, we awoke the other men who were still asleep, and all four of us got out of that blazing inclosure in a hurry.  One-half minute more and the flames would have seized upon our only means of exit, the little lane through the heap of gabions, and doubtless we should have been roasted to death, as there was no other possible way to get out.

The fire was now under great headway.  It would not do to let all the gabions burn up, so with the help of some army butchers who were camped near by, we set briskly at work on the windward side of the heap, overhauling them, and cutting a passage through ahead of the flames.  After about an hour’s lively work, we succeeded in saving about two-thirds of them.

As soon as daylight appeared we began to fix up matters as best we could, removing the traces of the fire, and piling up the remainder of the gabions in as near the former shape as possible, agreed to keep still about it, for fear e should be charged with neglect of duty or sleeping at out post.

When the new guard arrived next day to relieve us, we returned to camp.  One of the party had lost his rifle, and as we passed by the camp of a regiment on the road, it became quite dark, he managed to borrow one that he saw sticking out under a tent.  Each of us lost something of his traps, but managed to obtain duplicates without exciting the curious inquiries of our comrades in camp, and secretly congratulated ourselves upon our narrow escape from being roasted to death in the midst of those gabions.

[George H. Allen, Forty-six months with the Fourth R.I. volunteers, pages 345 - 347]

Civil War engineers had a lot of the same problems.  But retaining walls were way too simple [and civilian].

They needed revetments.

Col. H. L. Scott, Military Dictionary, Comprising Technical Definitions, Information of Raising and Keeping Troops, Actual Service, Including Makeshifts and Improved Materiel and Law, Government, Regulation, and Administration Relating to Land Forces will be cited as [Scott, Military Dictionary]

D. H. Mahan, A Treatise on Field Fortifications, Containing Instructions on the Methods of Laying Out, Constructing, Defending, and Attacking Intrenchments, with the General Outlines Also of the Arrangement, the Attack, and Defence of Permanent Fortifications will be cited as [Mahan, Treatise on Field Fortifications]

Q. A. Gillmore, Engineer and Artillery Operations Against the Defences of Charleston Harbor in 1863; Comprising the Ascent upon Morris Island, the Demolition of Fort Sumter, the Reduction of Forts Wagner and Gregg with Observations on Heavy Ordnance, Fortifications, Etc. will be cited as [Gillmore, Charleston Operations]

Capt. J. C. Duane, Manual for Engineer Troops will be cited as [Duane, Manual for Engineer Troops]

REVETMENTS

The interior slopes of the parapets of permanent and field-works, as well as in some cases the sides of the ditches of the latter, require revetments to enable them to stand at that slope which is necessary, arid to endure the action of the weather.

[Scott, Military Dictionary, page 504]

A revetment consists of a facing of stone, wood, sods, or any other material, to sustain an embankment, when it receives a slope steeper than the natural slope.

In field works revetments are used only for the interior slope of the parapet and for the scarp ; for the first sods, pisa, fascines, hurdles, gabions and plank, are chiefly used ; and for the last, timber.

Sod Revetment

Sod work forms a strong and durable revetment.  The sods should be cut from a well-clothed sward, with the grass of a fine short blade, and thickly matted roots.  If the grass is long, it should be mowed before the sod is cut.

Sods are of two sizes, one termed stretchers, are twelve inches square, and four-and a-half inches thick; the others, termed headers, are eighteen inches long, twelve inches broad, and four and-a-half inches thick.

The sod revetment is commenced as soon as the parapet is raised to the level of the head of the banquette.  A course of sods is then laid, either horizontal or a little inclined from the banquette; the course consists of two stretchers and one header alternating, the end of the header laid to the front.  The grass side is laid downward; and the sods should protrude a little beyond the line of the interior slope, for the purpose of trimming the course even at top, before laying another, and to make the interior slope regular.  The course is firmly settled, by tapping each sod as it is laid with a spade or a wooden mallet; and the earth of the parapet is packed closely behind the course.  A second course is laid on the first, so as to cover the joints, or, as it is termed, to break joints with it; using otherwise the same precautions as with the first.

The top course is laid with the grass up; and in some cases pegs are driven through the sods of two courses to connect the whole more firmly, which is, however, by no means necessary to form a strong sodding.

When cut from a wet soil, the sods should not be lain until they are partially dried, otherwise they will shrink, and the revetment will crack in drying. In hot weather the revetment should be watered frequently, until the grass puts forth.

The sods are cut rather larger than required for use; and are trimmed to a proper size from a model sod.

[Mahan, Treatise on Field Fortifications, pages 36 – 37]

Sods or turfs are used for the formation of the interior slopes of parapets, and the cheeks of embrasures.  Sods
should be cut from fine close turf, with thickly matted roots, previously mown, and if possible, watered, to make the earth adhere more closely to the roots of the grass.

The sods are laid, with the grass downwards, alternately headers and stretchers, like bricks in a wall.  Their under
or upper surfaces should be perpendicular to the slope of the parapet, and not horizontal, except in a vertical revetment, and each sod should be fastened to those beneath, by two or three wooden pegs.

Sod work can be made with great perfection, and is very durable.  In meadows, the dimensions of sods may be from 12 to 18 inches long, 12 inches wide, and 4 to 6 inches thick.  In heath, having large roots, they may be 2 feet long, 12 or 18 inches wide, and 8 to 10 inches thick.

To find the number of sods required to revet any given length of slope, the revetment being one sod thick: Divide the height of slope by thickness of sods, for the number of rows.  Divide twice the length of the slope by the sum of the length and breadth of a sod for the number in one row.  Multiply these two quotients together, for the whole.

Scott, Military Dictionary, pages 508 – 509]

Pisa Revetment

Ordinary earth, if mixed with a proper proportion of clay, and the whole well kneaded with just water enough to cause the particles to adhere when squeezed in the hand, may be used for a revetment, and is termed a pisa revetment.  Sometimes chopped straw is mixed up with the mass to cause it to bind better.

The pisa is laid in layers of twelve inches thick, and two feet broad, and well packed.  The same precautions should be taken in forming the parapet behind it as in sod revetments.  The face of the revetment may be sown with grass seed or oats, and when the stalk comes to maturity it should not be cut, but suffered to remain as a kind of thatch to protect the facing from the weather.

[Mahan, Treatise on Field Fortifications, page 37]

Pisa Revetment

We found another way wet earth was used as a way to cover other material.  During the siege of Confederate Fort Wagner, the direct approaches to the fort were on the beach.

[Gillmore, Charleston Operations, page 304]

Plank revetment

This revetment may be made by driving pieces of four-inch scantling about three feet apart, two feet below the tread of the banquette, giving them the same slope as the interior slope.  Behind these pieces, boards are nailed to sustain the earth.

[Mahan, Treatise on Field Fortifications, page 40]

When it was impractical to obtain finished lumber, logs were used for both revetment and the upright poles to hold it in place.  Looking at period photographs, it appears 6 – 8 inch logs were preferred, cut 10 – 12 feet long, held in place by 6 – 8 inch poles.  This makes sense – thick enough to do the job, a reasonable number to achieve the height of the interior slope, reasonable length and manageable weight.  If thicker logs were used, say 10 inch or 12 inch, they were split in two to lower weight and maximize coverage.

It’s also clear from period photos different builders used different schemes to put up plank and timber revetments.  Like all aspects of field fortifications, there were the endless variations on the theme.

Here is a picture of a field fortification built under the worst conditions possible:  under fire, limited material, limited tools.  These works were built in a desperate attempt to save lives – the lives of the soldiers who built them.  Nothing fancy here.  Cut enough logs to build a wall just high enough to kneel behind.  Throw up as much dirt as possible.

The ditch isn’t visible from the camera’s position – the earth had to come from somewhere, though.  In this case, we believe, from the other side of the visible parapet.  We can clearly see only a little bit of the earth thrown against the logs: just at the front, under the lens.  It’s entirely possible, given the situation, there were stretches of the parapet with little or no earth thrown up.  NPS built two replicas of this type of field fortification at Spotsylvania.  One, dating to the 1930′s and not well-maintained today, lies at the northern end of the Confederate “second line” just behind the “bloody angle”.  A few neglected pieces of timber mark the spot on the north side of the trail.  The original Confederate line ends at the south edge of the trail.  The second, an auto tour stop today, is located near the spot where the Confederate line crossed Brock Road.

The next photo shows “the middle ground” – more substantial, more uniformity in materials and construction.  Just for fun, we’ll add a little wrinkle.

The photograph shows two different methods engineers used to secure timber revetments.  Notice where the change occurs?  To the right, logs held in place by uprights.  Then about six sections to the left of the opening for Baxter Road – logs split, notched and held in place by smaller pieces run into the parapet.  Here is how the engineers drew these in profile:

One better than the other?  Support into the parapet.  A parapet would have to be very badly damaged before this construction loses its shape, so less maintenance.  Downside?  More labor, more tools.  Supports into the parapet were built as the parapet was erected, so not a good retrofit.

In the photo, you can see how the uprights are starting to lean, and the revetment to the immediate right of Baxter Road is coming apart.

To show there was no truly standardized revetment, here the engineers placed the logs  vertically.  Good use of material given the taller parapet?  Maybe.  We notice, however, the engineers used a combination of materials for longer stretches.

Tall Parapet - Log Revetment Vertical Construction

The field fortifications shown in the next two photos were built without any duress from enemy presence, ample supply of material readily available and a permanent garrison with plenty of time to maintain them, in other words, the most ideal conditions possible.  These were field fortifications right out of the engineer’s text book.

Here is a period photograph of the interior of a fort in the Defenses of Washington showing a plank revetment with the lumber placed vertically.

Plank Revetment - Vertical

Here, the engineers opted to use the traditional horizontal construction.

Plank Revetment - Horizontal Alignment

During the Petersburg campaign, the need for finished lumber was enormous.  A small city was built at City Point VA in addition to the miles of earthworks with wooden revetment, not to mention the miles of corduroy roads.  So where did all the lumber come from?

A lot of it was quartermaster purchases.  Facilities at City Point included a lumber dock to handle the inventory.

City Point - Stacked Lumber

Three sawmills were erected and run under the supervision of the Army of the James engineers.  From 1^st Lieut. Peter S. Michie’s report summarizing engineer activities July 1864 – June 1865, this entry from November 1864:

 While attention was paid to the defensive operations we also found time to collect, repair, and put in working order three saw-mills, which were located in a splendid forest in the Bermuda woods.  By these mills from 7,000 to 10,000 feet of lumber were sawed per day, the greater portion of which was used in the construction of a permanent hospital at Point of Rocks.  Sufficient was obtained, however, to stock the engineer depot and build platforms and magazines in all the batteries, wharves, and bridges on the river.

[OR Series 3 Vol. 5 page 190]

By March 1865, Michie was ready to brag a bit about his sawmills:

 Owing to the facilities we have here at present I have the honor to propose that we furnish the Engineer Department at Washington with such oak lumber, of the best quality, cut to any size, that may be required.  There are a great many white-oak trees here which might as well be used for this purpose as not.  This will only cost the Government transportation, and will save the $70 or $80 a thousand feet, which is about the price at present, buying from the market.

[OR Series 1 Vol. 46 Part 1 Chapter LVIII page 373]

We’ve seen the same proposition phrased as a question by, we think, Farquhar, in 1864.  We searched until our eyes crossed but can’t find it.  Paraphrasing – the engineer asked “why are we buying lumber at $60 or $70 a thousand [that's how I remember it]when we have all the white oak we can cut right here”.  Well, boys, you might be great engineers, but you don’t know beans about the power of a government contact in the hands of a great politician.

We don’t know what these sawmills looked like.  An educated guess is a standardized steam-powered design, based on this description:

SAW-MILL, (PATENT, UPRIGHT, PORTABLE.) It is composed of eight pieces of timber, from five to eight feet long; four pieces of plank, from four to six feet long; and about fifteen hundred pounds of iron; besides two long bed-pieces, a carriage, some small wooden fixtures, pulleys, etc.

The common up-and-down saw, six and one-half or seven feet long, is used without sash-gate or muley, and will saw timber of the largest or smallest size. It is so very simple in its construction that it has but few bearings, and consequently but little friction, and will therefore require much less power to drive it than the more complicated mills now in general use.

As much of the cumbrous machinery of other mills, such as large, heavy frames, sash-gates, etc., is dispensed with in this, it is much less liable to get out of order; while its simplicity enables any one of ordinary mechanical ability to repair or build it.  The amount of repairs required with fair usage is of insignificant import. The great advantage of such a mill for military purposes is its portability.

The engines and boilers furnished with these mills are constructed specially for it. The first size is a boiler 10 feet long, 24 tubes 2 1/2 inches in diameter, and 7 1/2 feet long, shell over the fire-box 44 inches in diameter, shell over the tubes 34 inches in diameter, and engine of 7-inch cylinder and 15-inch stroke.  This is a large eight-horse power, and is sufficient to drive the mill with any rapidity in the hardest and heaviest timber. It is sold with the mill – the whole establishment weighing about 6,500 pounds for $1,250.

The second size is a boiler 11 1/2  feet long, 25 tubes 2 1/2 inches in diameter, and 7 feet long, shell over the fire-box 44 inches in diameter, shell over the tubes 34 inches in diameter, engine same as that described above, (7-inch cylinder and 15-inch stroke,) excepting that it has extra connections.  It may be rated as good ten-horse, and is capable of driving the mill, together with some other machinery at the same time, such as circular-saw for sawing slabs, lath, and other light work.  This power is recommended.  It is sold with the mill – the whole weighing about 7,500 lbs., for $1,400.

In these prices smoke pipes, connections, and everything necessary for running are included.  The mill may be put up and at work in two or three days after its receipt at any given place.  It is said to saw three thousand feet a day, and has been made to saw nine hundred feet per hour.  With an exhaust pipe on the smoke stack the sawdust may be used for fuel.

[Scott, Military Dictionary, pages 545 – 546]

We can’t be certain where the sawmills were situated.  We telephoned Mr. Robert Krick at Richmond National Battlefield, but he wasn’t sure.  A little research with period maps and the 1860 census shows two civilian sawmills in areas under firm Union control: on the Curl’s Neck loop of the James River [handy to the Deep Bottom Federal lines] and near the village of Prince George Courthouse [shows as "mill" on period maps - census lists occupation of family members as "sawyer"].

The Prince George Courthouse location doesn’t match Michie’s description [not in the Bermuda Hundred region], but we’re reluctant to completely discount either possibility.  Even if the army purchased its own “portable” sawmills, why wouldn’t they use higher-volume civilian operations if available?  Hopefully, more research will lead to better information.  Some trip to the area, we want to spend some time looking at local newspapers and business publications.

Sand Bag Revetment

Sand-bags are coarse canvas bags, of a capacity sufficient to hold about a bushel of earth ; when empty they occupy only a small space, and are frequently of great use.

A good field-revetment can be built with filled sand-bags, laid as sods; such a revetment, however, is only fit for temporary purposes, as the sand-bags soon rot; they are unfit for lining the cheeks of embrasures, as the flash of the guns speedily destroys them.

In rocky positions, it is sometimes necessary to construct entire batteries and parallels with filled sand-bags.  Many of the British trenches and batteries before Sebastopol, owing to the rocky nature of the ground, were formed of sand-bags, baskets, casks, &c., filled with earth brought from a distance.

Sand-bags are used in great numbers, laid on the superior slopes of parapets, to form loop-holes for riflemen.

[Scott, Military Dictionary, page 509]

Sand bags are sometimes used for revetments when other materials cannot be procured; though their object, in most cases, is generally to form a speedy cover for a body of men.

They are usually made of coarse canvass; the bag, when empty, is two feet eight inches long, and one foot two inches wide; they are three-fourths filled with earth, and the top is loosely tied.

From their perishable nature, they are only used for a temporary purpose, as when troops are disembarked on an enemy’s coast.

[Mahan, Treatise on Field Fortifications, pages 40 - 41]

Notwithstanding Mahan’s comments, during the Civil War sandbags were used extensively by both sides whenever and wherever they were available.

Sandbag Revetment

On Morris Island, where the soil was either beach sand or marsh sediment with the consistency of “jelly”, they were the revetment of choice in the siege of Fort Wagner [despite the mention of Ft. Pulaski, used for comparison by Maj. T. B. Brooks, who wrote this portion of Gillmore's report]:

[Gillmore, Charleston Operations, pages 247 - 248]

Description of soil:  Col. Serrell’s report [Gillmore, Charleston Operations, page 276]

In preparation for the Spring 1863 offensive in Virginia, Chief Engineer of the Army of the Potomac Lieut. C. B. Comstock (also involved with the 46,000 sandbags at Fort Wagner), wrote to the army’s Chief of Staff Major-General Daniel Butterfield:

In case a siege of Richmond is deemed among the possibilities of the coming campaign, I think the chief quartermaster should be notified that he may be called on to furnish on our arrival in front of Richmond 10,000 shovels, 5,000 picks, 5,000 axes, and 2,000 shingling hatchets; that the Engineer Department should hold in readiness 30,000 sandbags, …

[OR Series 1 Vol. 51 Part 1 Chapter LXIII page 999]

The “possibilities of the coming campaign” were rather rudely abbreviated in the fields and hilltops around Mr. Chancellor’s crossroads.  Today, one can visit the spot where Gen. Jackson’s arm isn’t.

Sandbags were often added to the top of earth parapets, affording extra protection for infantry and gun crews from musket fire.  Confederate sharpshooters were a constant threat along portions of field fortifications at Petersburg from the Appomattox River to Fort Davis, so sandbags atop of parapets were a common sight.  Not only did the extra height protect anyone close behind a parapet, the sandbags were often arranged to provide a firing hole for Union sharpshooters. [Earl J. Hess, In the Trenches at Petersburg, Field Fortifications and Confederate Defeat, pages 51 – 53]

Sandbags Arranged as Sharpshooter Loopholes

In some cases, Union Fort Conahey in this example, sandbags were built into the initial design of an earthwork:

Profile of Fort Conahey with Sandbags on Superior Slope

Carried through to completion:

Sandbags on Parapet

Was revetment necessary?  Not necessarily.  Sometimes, depending on the soil and with decent maintenance, parapets held their shape pretty well.  Here are four photos to illustrate the point.  The first is Confederate Fort Darling in its heyday.  The second is the same spot today.  The third is a poorly maintained epaulment in the Confederate defenses in Atlanta.  The fourth are works [Union, we believe] near Petersburg badly in need of repair.  Most of the time, probably, revetment was needed to hold a parapet’s shape.  Maintenance was a prerequisite all the time.

Fort Darling

Fort Darling Today

Poor Maintenance

Deferred Maintenance

Scarp revetment

This revetment is formed of a framework of heavy timber, and is used only for important field forts.  A piece, termed a cap, or cap sill, is imbedded in a trench made along the line of the Berm; other pieces, termed land-ties, are placed in trenches perpendicular to the cap, with which they are connected by a dove-tail joint; they are about eight or ten feet asunder, pieces are halved into the land-ties about two feet from their extremities, and two square piles, about five feet long, are driven into the angles between the land-ties and cross pieces; inclined pieces, which serve as supports to the cap, are mortised into its under sides at the same points as the land-ties.

These supports usually receive a slope of ten perpendicular to one base; they generally rest on a ground-sill at the bottom of the ditch, to which they are mortised, this sill being held firm by square piles.  The ground-sill may be omitted by driving the supports below the bottom of the ditch.

Behind this framework, thick plank, or heavy scantling, is placed side by side, having the same slope as the supports; or else a rabate [spelling is correct – we can’t find a definition] may be made in the cap and ground-sills, and the scantling be let in between these two pieces serving as a support to the cap.  This is the more difficult construction but it is the better, since, should the heavy support be cut away, the cap will still be retained in its place.

Mahan's Illustration of Scarp Revetment

Scarp revetments are sometimes formed by laying heavy timber in a horizontal position; but this method is bad, as it enables the enemy to gain a foot-hold by thrusting their bayonets between the joints.

The length of the land-ties should be at least equal to two-thirds the depth of the ditch.

The counterscarp is seldom reveted.  A framework similar to that for the scarp might be used, and thick boards, laid horizontally, be substituted for the inclined scantling.

[Mahan, Treatise on Field Fortifications, pages 41 – 42]

From the Official Records, mention of scarp revetments:

Defenses of Cincinnati:

… At Fort Mitchel the new portion was completed as to parapets, ditches, glacis, drainage, and gate.  The postern, communicating under parapet with ditch on the south curtain, half done.  Timber cut, excavation finished, and work half done on scarp revetment of old portion of south curtain.  Southwest bastion of old work removed. …

Capt. M. D. McAlester, monthly report for July 1863 dated August 11, 1863 [italics and emphasis added]

[OR Series 1 Vol. 23 Part 2 Chapter XXXV pages 607 – 608]

New Creek, West Virginia:

… Extensive repairs are needed in the scarp revetment of the fort at New Creek. The gorge should be closed, leaving merely a passage to be obstructed when required by a barrier. … [italics and emphasis added]

Report of Major C. Seaforth Stewart dated December 9, 1864.

[OR Series 1 Vol. 43 Part 1 Chapter LV page 655]

Defenses of Washington:

… Fort Albany: Scarp revetment has been repaired, and some alterations in platforms and embrasures made. … [italics and emphasis added]

… Revetment of scarps will be required either by sodding the whole exterior slopes at all the forts on the line not already revetted on an angle of 45 degrees by a scarp wall of brick or stone, or by a scarp revetment of plank. … [italics and emphasis added]

Report of Lieut.-Col. B. S. Alexander dated October 4, 1864

[OR Series 1 Vol. 43 Part 2 Chapter LV page 282 and page 284]

Detroit, Michigan:

… Fort Wayne, Detroit, Mich., in charge of Capt. C. B. Blunt, Corps of Engineers.  Since the last annual report about $900 derived from the fund for contingencies of fortifications has been expended in renewing a length of 150 feet of the timber scarp revetment. The barracks remain unfinished, and the quarters destroyed by fire several years since have not been rebuilt. The work can be prepared for its armament in a short time.  To construct a stone revetment for the scarp will require the sum of $100,000. [italics and emphasis added]

Annual report for the year ended June 30, 1861, Bvt. Brig-Gen Joseph G. Totten to Secretary of War

[OR Series 3 Vol. 1 page 685]

Confederate Fort Harrison / Union Fort Burnham – Bermuda Hundred VA

… At Fort Burnham the scarp revetting damaged by the recent heavy rains has been repaired…” [italics and emphasis added]

Bvt. Major Peter S. Michie’s report for the week ended March 11, 1865

[OR Series 1 Vol. 46 Part 1 Chapter LVIII page 375]

That’s enough for this article.  We’re not done with revetments, though.  There are three basic types of revetments yet to cover:  hurdle, gabions and fascines.  There’s a lot of material on them in the literature, so they merit separate treatment.  We’re also going to do a short article just on embrasure revetment.

CORPS OF ENGINEERS

Duties of the officers during the year – The Corps of Engineers consisted of eighty-five officers, the Military Academy, its officers and professors, and the battalion of engineer soldiers of five companies.

Of the eighty-five officers of engineers embraced in the corps, fifty- four were on detached duty commanding army corps, divisions, and other military organizations; on staff duty and as engineers and assistant engineers with armies operating against the rebels; in command of the pontoon-bridge service, and in command of the troops of the engineer battalion; and thirty-one on duty superintending sea- coast defenses, lake surveys, lake and sea-coast harbor improvements, Military Academy, and assisting the Chief Engineer in connection with all these duties.

Every officer of the corps has been on continued and uninterrupted duty during the entire year, and four of its members have died in service.

The loss in officers killed and who have died in service from wounds and other causes during the rebellion is fourteen.

Twenty-one of the members of the corps still remain on detached service performing important duties growing out of the rebellion, which prevent their returning to engineer duty.

The value and estimation in which the military talents and practical knowledge of the officers of the corps are held have, by contributing to the command of the armies and for staff service, together with the loss of those who have given their lives to the defense of their country, greatly reduced its numbers and efficiency for the many duties devolving upon it. Many of those of highest rank and experience are still on detached service, and the vacancies from casualties have necessarily been filled by junior members, recent distinguished graduates of the Military Academy.

Although the legal strength of the corps is sufficient to perform the proper functions of its members, the present assignment of its officers renders it impracticable to meet the numerous demands upon the department.

For a comprehensive knowledge of the duties of the engineers, a recurrence to the general objects of the campaign is necessary.

It will be recollected that by descending the Shenandoah and crossing the Potomac above Harpe’rs Ferry the rebel army in 1864 threatened Washington, Baltimore, Pittsburg, and even Philadelphia, as also intermediate cities.  Washington City had become the great depot for immense supplies for all arms of service for months in advance.  An extensive ordnance depot, a navy-yard, the general hospitals, the archives of the Nation, its Executive and judiciary, with the public edifices for all national purposes, was the rich prize, to gain possession of which the rebel authorities directed their efforts, as well as to divert our armies from the attack on Richmond.  At Antietam and South Mountain they had been defeated and driven back into the Valley of the Shenandoah.  Again they made a powerful effort and were defeated at Gettysburg and driven across the Potomac and up the valley.  In July, 1864, after the lieutenant- general had forced the rebel armies concentrated under Lee from Todd’s Tavern, through Spotsylvania and Cold Harbor, into Richmond and Petersburg, they made another effort to divert the lieutenant-general by detaching Early on another expedition down the Valley of the Shenandoah and across the Potomac, threatening Baltimore by moving on the Monocacy, where a small body of our troops were repulsed, thus jeopardizing both Baltimore and Washington.  The attention of the lieutenant-general was given to these efforts of his adversary to divert him from his main object – the defeat and capture of Lees army – and, while withdrawing part of the garrison to re-enforce the armies operating against Richmond, he held the command of his rear and Washington by being enabled to transport from before Petersburg as large a force as Lee could detach to operate in the valley and on Washington.  Many thousands of wounded and sick occupied the hospitals in Washington, and the troops fit for duty did not suffice to man the armaments of the forts around the city.  The engineers had previously constructed a system of detached redoubts and forts around the city on a circuit of upward of thirty-five miles.  Early, after his success at Monocacy, moved directly upon the defenses of Washington between the Potomac and the Eastern Branch.  Colonel Alexander, of the Corps of Engineers, was the only officer of the corps whose personal attention could be given to these defenses.  Colonel Woodruff and Major Kurtz, of the Corps of Engineers, and assistants of the Chief Engineer, were first ordered to these defenses.  Subsequently all the officers on the sea-coast, north and east of this city, were detached from their labors of constructing sea-coast batteries (then threatened by rebel iron-clads building in Europe, as another effort to divert our armies in the field), and were ordered to the defenses of Baltimore and Washington – Major Prime, Captain Robert, and Lieut. J. A. Smith to the aid of Colonel Brewerton at Baltimore, and Colonel Macomb, Major Blunt, Major Casey, and Captain Tardy to the aid of Colonel Alexander at Washington.  The rebel blow was aimed at Washington.  The wise foresight of the Secretary of War had caused all the employees of the several bureaus of his Department to be organized and drilled as infantry troops.  The necessity for the withdrawal of the Sixth Army Corps from Petersburg and of the Nineteenth from New Orleans had also been foreseen, and orders sent to them to proceed to this city to meet the blow that was threatened.  The Veteran Reserves and convalescents from the hospitals were also ordered to garrison the defenses.  Requisitions were made upon the Governors of States to furnish troops, but with little success. The Sixth and Nineteenth Corps arrived at the most opportune moment.  Early directed his efforts upon Fort Stevens, but finding the garrison re-enforced, and even moving out of the defenses to meet him, he suddenly retreated across the Potomac and up the Valley of the Shenandoah.  The engineers were then ordered to their former stations on the sea-board.

Early was pursued by Sheridan with his cavalry and the troops that drove him from Washington up the Shenandoah, defeating him and his re-enforcements, and eventually annihilating his army.  For this expedition Major Stewart, Captain Gillespie, and Lieutenant Meigs, of the Corps of Engineers, were assigned.  In the death of Lieutenant Meigs, while reconnoitering in the neighborhood of Winchester, the corps lost one of its most meritorious and valued members.  Captain Gillespie accompanied Sheridan’s expedition to the James River, destroying the rebel communications on that river and all others west and north of Richmond, and finally joined the lieutenant-general before Petersburg.

With the investment of Petersburg commenced a series of laborious and difficult engineering operations by the Army of the James and the Army of the Potomac.  The narratives collated from the reports of Colonel Michler and General Michie give the details of these operations.  A reference to plan No. 12 will explain the extent of the defenses about Petersburg and Richmond and the labors of our engineers about Petersburg and the rebel defenses on the north side of the James River.

The rebels after being defeated by the army under Lieutenant- General Grant and driven from their intrenchments around Petersburg, extending to the Hatchie [Hatcher's Run?], evacuated that city on the 2d of April, 1865.  The evacuation of Richmond followed on the 3d of April, when the rebel army under Lee retreated, and was closely pursued and pressed to Appomattox Court-House, where it yielded to the superior prowess and skill of the armies of the United States, on the 9th of April, 1865, thus breaking up all semblance of rebel authority, leaving Sherman to end it by the capture of Johnston on the 23d of April.  A map of this campaign is in progress, awaiting information yet to be collected to perfect it as an historical record of these ever-memorable military operations which resulted in restoring the power and union of a nation.

After the evacuation of Richmond the rebel chief and his advisers, who devised this most unjust and unwarrantable scheme to destroy a nation, sought safety in flight toward Georgia.  Their movements had been foreseen, and were provided for by a brilliant campaign of a cavalry force under General James H. Wilson (captain of the Corps of Engineers), who posted his troops with great discrimination and judgment, and succeeded in capturing the leader at Irwinton [Irwinville] on the 10th of May, 1865.

From Atlanta the grand army of the West, commanded by Sherman, commenced moving for the sea-coast, while Thomas occupied Tennessee and Kentucky.  The rebels under Hood on evacuating Atlanta operated on Shermans previous line of march.

The labors of the engineers at Chattanooga under Colonel Merrill, and the volunteer engineers, had rendered this important position as well as Knoxville impregnable; and Hood retrograded toward the Tennessee River with a force so far superior to Thomas as to cause the latter to fall back gradually upon Nashville.  The labors of the engineers in fortifying Franklin, on the Harpeth River, did not suffice, with a single army corps under Schofield, to hold those intrenchments.  Our army fell back to Nashville, where much labor and the skill of the engineers had previously been bestowed in fortifying it by General Morton, Colonel Merrill, Captains Barlow and Burroughs, and other junior officers of the Corps of Engineers, together with volunteer engineers.  In September, 1864, Major Tower, Corps of Engineers (brevet major-general of volunteers), took charge of these defenses, and perceiving the great importance of Nashville as a depot of supplies, as well as other important strategic advantages, commenced to add to and perfect the fortifications (see plan No. 4), on which he continued unremittingly until Hoods advance and investment of the place on the 13th and 16th of December, 1864 [sic].

During the few days preceding Hoods arrival before Nashville, Thomas had concentrated his several available army corps within the fortifications of Nashville, the plan of which is given on plate No.4.

The importance of these defenses was mainly in enabling Thomas to concentrate his army at a depot well stored with munitions of war, and to hold his enemy, flushed with his successful march from Atlanta, in check until he was ready to take the field.

The accompanying plan of the fortifications (No. 4) by General Tower and annexed extracts from his report explain more fully the successes of this most important advance of Thomas, resulting in the demolition and annihilation of the rebel power in Tennessee.

During the same eventful period the fortifications that had been constructed by the engineers at Murfreesborough were successfully held and defended by a part of Thomas army.  Colonel Merrill, captain of engineers, with the volunteer engineers, had during the year given special attention to fortifying all the important points on the railroads in Tennessee and part of Kentucky, while Lieutenant-Colonel Simpson, Corps of Engineers, had fortified Cincinnati, Ohio; Covington and Newport, Frankfort and Louisville, Ky., and the lines of the Louisville, Nashville and Kentucky Central Railroads, thus covering Thomas rear and defending his lines of communication.

Such is a general outline of the labors of the engineers in Tennessee.

The march of the grand army of the West under Sherman (see plan No. 3) did not call for offensive or defensive fortifications.  The labors of the engineers, Captain Poe (brevet brigadier-general, U. S. Army), Captain Reese (brevet brigadier-general, U. S. Army), Lieutenant Stickney (brevet major, U. S. Army), Lieutenant Ludlow (brevet major, U. S. Army), and Lieutenant Damrell, were most advantageously bestowed upon the roads and bridges, and reconnoitering the enemy’s movements and positions. (See annexed narratives.)

The pontoon trains under charge of these officers were indispensable to the success of the army.  They consisted of canvas boats, which proved serviceable for the march of this army from the Tennessee to its final disbandment in Washington City in 1863. The advantages of these light trains, their frequent use during the campaign proving their adaptation to our country, are fully developed in the narrative collated from Poe’s and Reese’s reports.

In September, 1863, Knoxville was captured by our force, and in November of the same year Chattanooga was occupied by our army. At the latter point Sherman concentrated his supplies and moved in force against the rebels, driving them through Ringgold, Tunnel Hill, Dalton, Resaca, Allatoona, and Kenesaw, to Atlanta.

At this latter place the rebel army was strongly intrenched.  The place was first invested by our army on the north and east, when, its strength being fully ascertained, Sherman marched his army to the south, defeating the rebels at Jonesborongh and Lovejoy’s, thus investing it on the south and compelling Hood to evacuate this stronghold.  The annexed narrative, collated from the report of Brevet Brigadier-General O. M. Poe, U. S. Army, captain of engineers, gives the important incidents connected with its capture, and furnishes plans of the rebel defenses. (See plan No. 2; see narrative annexed.)

While these movements and successes of the armies under Thomas and Sherman were in progress, General Grant ordered a division of his army under General Terry to co-operate with the navy in the reduction of the defenses of the mouth of Cape Fear River in January, 1865.

Captain Comstock, of the Corps of Engineers (lieutenant-colonel, aide-de-camp, brevet brigadier-general of volunteers), had charge of the engineer operations of this expedition.

Fort Fisher, situated at and commanding the northern entrance of this river, was found to be the key of the position. Plans Nos. 5 and 6 give the details of the defenses constructed by our army to cover its landing and its rear while operating on Fort Fisher.

A bombardment by the fleet, resulting in dismounting many of the guns on the land front of the work, as well as cutting the electric wires for exploding a formidable system of mines on the same front, preceded a successful assault by the troops under General Terry.

The accompanying plans Nos. S and 6, with extracts from General Comstock’s report, give the details of the rebel fortifications and those thrown up by our troops. (See General Comstock’s report, annexed.)

Later in the season General Canby concentrated the troops under his command and moved to the attack of the city of Mobile, having the co-operation of the navy. The labors of the engineers under Captain McAlester (brevet major, U. S. Army), Captain Palfrey (brevet lieutenant-colonel, U. S. Army), Lieutenant Burnham (brevet major, U. S. Army), and others, were here called into requisition.

Blakely (see plan No. 7) was invested, batteries constructed and opened upon the formidable rebel batteries covered by strong intrenchments, with abatis surrounding their entire position, with its flanks resting on the Blakely River.

Plan No. 7, with extracts from the report of Major McAlester, gives the details of the operations, final assault and destruction of the rebel defenses on the 8th of April, 1865. (See McAlester’s report, annexed.)

Spanish Fort was at the same time invested by our army, and the more formidable siege operations of a first and second parallel with approaches and enfilading batteries became necessary, and resulted finally in the capture of the rebel defenses by assault, on the 8th and 9th of April, 1865. (See plan No. 8.)

These defenses and approaches are given in detail on plans Nos. 7 and 8, which, with extracts from Major McAlester’s report, will explain and illustrate this well-designed and skillfully executed siege.  The fall of Blakely and Spanish Fort caused the rebel army under Taylor, Gardner, and Maury to evacuate Mobile, and retreat to the north.

Plan No. 9 gives the formidable rebel defenses of the city of Mobile, surrounding it with three lines of detached forts and connecting intrenchments, with the flanks resting on Mobile River. The skillful labors of the rebel engineers about this city were very extensive and the system exceedingly strong.

The determination of the commanding general to turn these works, by first reducing Blakely and Spanish Fort, proved successful, and the character of the works as shown on the plan forcibly illustrates the saving of lives and treasure in not first attempting to reduce these powerful defenses.

Plan No. 10 gives the position of the entire and connected system of rebel defenses that succumbed to the skill and talent of Canby.

While these important operations were in progress in Tennessee and Alabama, Sherman, with the grand army of the West, and Lieutenant-General Grant, with the combined Armies of the Potomac and the James, together with the garrison of Washington City, were simultaneously leading the national forces to strike a final blow to rebel power, and enforce the restoration of national authority from the Atlantic to the Pacific. (See plan No. 3)

Sherman’s army reached the sea-coast, by first capturing Fort McAllister, on the 13th of December, 1864, by Hazen.  The strong rebel intrenchments at Savannah were then invested, and the rebel General Hardee driven from them across the Savannah River. The department has as yet received no plans of Fort McAllister or of the defenses of Savannah.  The labors of the engineers of Sherman’s army (see Poe’s narrative) were again bestowed principally in reconnoitering the enemy’s positions, and maneuvering the canvas pontoon trains to cross the army over the several rivers between Savannah and the last water-course crossed in pursuit of rebels.  The success of these bridge trains is given in the extracts from Generals Poe’s and Reese’s reports.  The city of Charleston fell into our power on the 18th of February, 1865, after its evacuation by the rebels in consequence of Sherman’s movements in its rear, and cutting off its supplies from the interior, while it was already blockaded by our fleet and invested by land by our army.

Schofield, after the reduction of the entire defenses of Smithville, moved upon Raleigh, and united his forces with those of Sherman. The engineer operations on this line were in reconnoitering and maneuvering the pontoon-bridge trains for the passage of the rivers, under Lieutenant Stickney (brevet major, U. S. Army), of the Corps of Engineers. (See Stickney’s narrative.)  After obstinately contested combats at Averasborough and Bentonville, the rebel power under Johnston was finally overcome and subdued by the capture of his entire command on the 23d [26th] of April, 1865; after which, by easy marches, the grand army of the West repaired to Washington City. (See plans Nos. 1, 11, and 12.)

The momentous campaign of the armies under the command of the lieutenant-general, with the purpose of capturing Richmond, and overthrowing the rebel authorities holding the semblance of Confederate power in that city, was commenced on the Rapidan in May, 1864.  The battles of Todd’s Tavern, on the 7th of May; of Spotsylvania, on the 14th and 19th, and passage of the North Anna, on the 24th; of Cold Harbor, on the 31st of May and 1st of June; the march thence and passage of the James River on the 16th, 17th, and 18th, with the investment of Petersburg on the 3d of July, 1864, constitute a brilliant series of grand battles and maneuvers that do not come within the scope of engineer reports.

The annexed narrative and information from the report of Colonel Michler, dated October, 1865, give more specifically the labors of the officers of the Engineer Corps during the progress of this campaign.

SEA-COAST AND LAKE DEFENSES

While most of the officers of the Corps of Engineers have been actively engaged in the field, as heretofore stated, others have given their attention to the important labor of sea-coast defenses.

Against predatory expeditions of rebel cruisers and iron-armored vessels, built in foreign ports claiming to be neutral, it was necessary to construct batteries to mount rifle artillery and smooth-bored ordnance of heavier calibers than heretofore used. Colonel Macomb, Major Blunt, Major Casey, of the Corps of Engineers, were employed in thus fortifying thirteen harbors on the Eastern coast. A t the same time progress on the permanent sea-coast defenses was continued at all the harbors from Maine to Hampton Roads, inclusive, at Key West and Tortugas, and at San Francisco; and repairing the permanent works on the Gulf of Mexico that were taken from the rebels, which had been more or less injured by them and by our attacks, to restore them to the Union.  On the Northern and Eastern works, as also on the California coast, the main object has been so to direct the operations as soonest to mount the contemplated armaments, which, at this time, are required to be of such penetrating and crushing power as will in all probability insure the destruction of any iron-armored vessels that can combat them.  The introduction of these increased calibers and this power of artillery has made it necessary to renew most of the gun platforms heretofore constructed, which were designed for no larger caliber than 42-pounders. At the present time no smaller gun is prepared for the sea-coast batteries than 100-pounder rifle guns, and ten to fifteen inch rifled and smooth-bored guns.

The further construction of the sea-coast batteries has been retarded by the necessity which now exists of so covering part of our guns and gunners as to render them secure against any advantage that an attacking power in iron-armored ships opposed to them shall possess.  So far as we have yet progressed, preparations for guns of large caliber have been perfected, and the guns mounted to throw, collectively, 147,150 pounds of metal at a single discharge, which is an addition during the year of 40,651 pounds of metal that can be so thrown against an enemy.

Continuing to increase the armament on our sea-coast in the same ratio for a reasonable time will render the harbor defenses exceedingly difficult for any maritime power to overcome, and, in combination with other auxiliary means of defense, will carry the cost and time requisite to subdue them beyond the means of foreign powers, provided we hold our works in a perfect condition for both land and sea attacks.

Boards of engineers have been detailed to consider what modifications are necessary at each and every work along our sea-coast to adapt them to resist the powerful armaments that European fleets, singly or combined, may be enabled to bring across the Atlantic, over the bars of our ports and harbors, to attack them.

The details of the operations during the year at the several works on the Atlantic, Gulf of Mexico, Lake and Pacific Coasts, derived mostly from the reports of the superintending engineers, are annexed.

PRISON DEPOTS

The prison depots also called for the labors of engineer officers.  Point Lookout, at the mouth of the Potomac, was subject to sudden attack from marauding parties and detached cavalry from armies operating against Baltimore and Washington, which, with the immense body of prisoners, made it necessary to fortify the position against attempts to liberate them by forts commanding both the interior and exterior.  Major Stewart, assisted by Lieutenant Cant- well, and afterward Colonel Brewerton, constructed these defensive works.

THE PRISON DEPOT AT JOHNSON’S ISLAND

Cleveland harbor, Lake Erie, had to be defended against attempts of the prisoners, and succor by water from expeditions organized in the friendly and neutral territories of Great Britain in Canada.  Major Casey and Captain Tardy were assigned to and performed this service, constructing a water battery at the mouth of the harbor, against a force approaching by water, and temporary field forts on Johnson’s Island.

SURVEYS, MAPS, AND TOPOGRAPHY

The surveys for the armies in the field, embracing the topography of the country passed over and particular sites occupied, have been referred to in other parts of this report.

The extent of the labors performed by the officers on duty in the Bureau has been the engraving, lithographing, photographing, and issuing 24,591 sheets for officers in the field and various branches of the service requiring this information, leaving still on hand a few copies of each publication for reference and the calls of the War Department.

The survey of the northwestern lakes has been in progress for several years, to obtain for the commerce of the States whose industry is promoted by that extended interior navigation the safety that a perfect and correct knowledge of the shores and bottom alone can attain.  It is being conducted under the direction of Major Raynolds, of the Corps of Engineers, upon the same scientific principles and with the same care and accuracy that has been bestowed upon the coast survey and other national geodetic surveys. During the year two maps have been prepared from the field-notes published and issued to the navigators of the lakes.  One gives the west end of Lake Superior and the other the northeastern part of Lake Michigan.  Three others have been prepared and are now ready for engraving, giving the Portage River and the Bay of L’Anse, on Lake Superior, and a third giving the north end of Green Bay.

Two thousand eight hundred and twenty sheets of the maps of the lake surveys have been issued for commercial, harbor improvement, and military purposes during the year, making the whole number of maps called for and issued since these surveys were commenced 27,411 sheets.

Special surveys have also been made during the year, maps issued and forwarded for the use of the department, of Niagara River, Erie, Conneaut, Ashtabula, Grand River, Cleveland, Black River, San- dusky, Saint Joseph’s, Grand Haven, Chicago, Racine, and Sheboygan.

SURVEYS

The principal labors of the parties engaged in these surveys during the year are comprised in the measurement of 269 1/2 miles of shore- line, 164 1/2 square miles of topography, 187 miles of soundings, and 1,200 square miles of offshore hydrography on 1,586 miles of lines of soundings; the measurement of a base line of 4,173 feet in length; difference of longitude between several distant points by electric observations, and observations by flashing lights; also astronomical observations for the latitude of eight points. Recommendation. – These surveys are called for by numerous parties and individuals, as well as by commercial men, for private as well as for public use.  It is indispensable that some rules and system be established to keep the issue of these valuable maps within such limits as will insure the great objects of the survey, the diffusion of this information to promote national industry, at the same time to prevent them falling into the hands of persons collecting for other purposes than the public good.  I recommend that the department be therefore authorized to issue these maps, after supplying the wants of the Government, at the cost of paper and printing, as is now and for years past has been authorized for distributing the Coast Survey maps.  This will prevent an improper use, and enable all persons capable of using them to obtain copies.

The estimate for carrying on the work for the next year is $184,604.42, which exceeds the amount appropriated for last year’s operations about $60,000.  It is proper to say that this increase of estimate does not contemplate any advance in the wages of assistants, but is simply due to the increased cost of materials and supplies.

On our Pacific Coast Major Williamson, of the Corps of Engineers, has explored and reconnoitered parts of Northern California and Southern Oregon, giving the topography of its roads, and continues observations for barometric correction of altitudes, having also in view an investigation of the formula for determining heights by this instrument.  He has traversed and explored the heights of the Nevada Range in Northern California, said to be 10,000 to 11,000 feet above the level of the sea, and the military roads between the coast and this range of mountains to facilitate the military operations of the commanding general.  During the year he also examined the various sites on Admiralty Inlet and Puget Sound, that might hereafter become useful for military purposes, and selected such as should be reserved from sale by the Land Office.

PRESERVATION AND REPAIR OF ATLANTIC HARBORS AND SEA-WALLS

An appropriation was made in 1864 for renewing the construction of the sea-walls in Boston harbor to preserve the headlands from further destruction by the ocean waves, and, as a consequence, injury to the harbor for commercial use, while at the same time it preserves important sites that hereafter will be occupied by batteries bearing on the channel leading to the city of Boston.  The following narratives of the operations on these islands are drawn from the report of Colonel Graham, the superintending engineer. The same officer was charged with the application of the appropriation of $100,000 for the preservation and repair of the harbors on the Atlantic.  The accompanying summary gives his views on this subject in relation to the Susquehanna River below Havre de Grace, dredging the Patapsco River, Portland Harbor breakwater, navigation of the Hudson River below Troy, and Delaware Breakwater.  Colonel Graham recommends additional appropriations for the Atlantic harbor improvements.

MILITARY ACADEMY

During the past year sixty-eight cadets completed their studies and military exercises at the Academy, and were commissioned as lieutenants in the Army.  This is the most numerous class that has ever graduated at the institution since its organization in 1802. For many years the number of graduates has not sufficed to fill the annual vacancies in the Army.

The number of officers in the several branches of the staff, and of regiments now comprising the Regular Army, has greatly increased from time to time, while the number of cadets authorized by law has remained unaltered since 1843.  The result is that neither the staff corps, nor regiments of artillery, cavalry, and infantry, can be furnished with the numbers to perfect their company organizations, and military science and art cannot be disseminated throughout the country in proportion to the increase of population and national interests to be protected.  The total number of cadets now at the Academy is 235, and the total number authorized by existing laws is 293.  From various incidents to which the appointments are subject, this ratio does not materially alter from year to year.

The average cost of the institution for the last twenty years has been $160,711.83.  The cost during the past academic year was $201,217.  These sums include the pay of cadets, officers, and professors, and all contingencies.  The annual average appropriation for twenty years is $166,684.63, and for the present year is $257,505.  This excess arises from the increase of the pay of cadets, and for increase cost of forage for artillery and cavalry horses, & c.

Recommendations. – To meet the wants of the military service, and to diffuse a knowledge of the science and art of war more extensively throughout our widely extended domain, I recommend at this time an increase in the total number of cadets of two additional appointments from each State and Territory and the District of Columbia, thus making the number of appointments to be authorized under the law to be one from each Congressional district and Territory and the District of Columbia, ten from “at large” annually by the President’s selection, and two in addition from each State and Territory and the District of Columbia.

The difficulties that have been experienced for years past in training the minds and bodies of the young gentlemen sent to the Academy to prepare them for usefulness as members of the military profession arise mainly from the qualifications of the candidates being so exceedingly limited.  While at the present time it may not be expedient to increase the standard for admission, I do urgently recommend that a selection from at least five candidates to be nominated for each appointment may be authorized by law, when every section of the country would more certainly have its due proportion of graduates entering the Army annually. Should this principle be authorized by law, the examination of the candidates could be ordered in several sections of the country at convenient military posts, and thus save a great annual expense now incurred by partially educating and returning deficient cadets to their distant homes, insure a much greater proportion of members who could master the course of studies, and avoid the numerous and frequent discharges from the Academy for inability to acquire the requisite information and proficiency for a graduate of this institution.

The accounts of the disbursing officers of the department have been regularly forwarded from month to month.  These accounts had accumulated in the department during the past four years beyond the means allotted to the financial branch to examine, correct, and forward to the Treasury Department for final settlement.

During the year 1,203 monthly accounts, amounting to   $11,834,308. 35, have been thus examined and forwarded to the Auditor for final settlement, and there remain on hand at this time 398 monthly accounts to be examined, amounting to $4,492,964. 85. At the rate of progress made during the past year in the examination of these accounts the work in a short time will be brought up to the months in which they are received from the officers. No defalcation or losses in any way exist in the disbursements and accountability of the officers of the department.

At the present time all property purchased for the armies in the field, either worn or of a perishable character, is being sold, and the avails will be returned to the Treasury.  The amount of sales to this date is $34,123.12.  The residue of this property is being stored in engineer depots for further use, at the Jefferson Barracks depot, Mo., and at the Willet’s Point depot, N. Y., under charge of engineer officers and troops of the Engineer Battalion.

The property of the department in the hands of its agents is accounted for quarterly, and the returns examined in this Bureau.

The number of returns examined during the year is 220

And remaining to be examined 43

Making the number of property returns rendered by officers 263

RICHD. DELAFIELD, General and Chief of Engineers U. S. Army

[OR Series 3 Vol. 5 pages 162 - 172]

The Official Records annexes reports submitted by others.  We will include these other reports with the military units associated with their authors, e.g., Lieut. P. S. Michie’s report is with the Army of the James.

Narrative from the report of Lieut. P. S. Michie, Corps of Engineers, brevet brigadier-general of volunteers

to

General Delafield, Chief Engineer U. S. Army, dated October 10, 1865. (See plans 11 and 12)

The Army of the James, consisting of the Tenth and Eighteenth Army Corps (and subsequently of the Twenty-fourth and Twenty-fifth), commanded by Maj. Gen. B. F. Butler, occupied a defensive position across the peninsula of Bermuda Hundred on a line 6,058 yards long, its right resting on the James River about one mile below the Howlett house, and its left on the Appomattox River, on the high ground across the creek, from and on the high ground overlooking Port Walthall.

This defensive line, from its position, was unusually strong.  With its flanks resting on and protected by two rivers, and its front of attack being diminished to about one-fourth of its length, because of impassable ravines, it was capable of being held by a much inferior force than the enemy were required to keep in its front.  But it had also its disadvantages; for the enemy intrenched on a line approaching not nearer than 800 yards, with flanks as secure as ours, and a front made unassailable by means of all the obstacles known to field defense, and thus effectually closed to our forces there every avenue to do damage to the railroad and turnpike, which were the lines of communication to the wings of the rebel army and the avenues to their capital.  The position of the two lines is given below in the sketch.

In addition to the line above described there was a strong work thrown up on Spring Hill, on the south side of the Appomattox River, just opposite Point of Rocks, and also strong works at Wilson’s Wharf and Fort Powhatan, on the James River, all of which were constructed and garrisoned by detachments from this army.

These latter commanded the channel of the river at very important points, and on their occupation depended the uninterrupted supply of the Armies operating against Richmond.

Brig. Gen. Godfrey Weitzel, U. S. Volunteers, captain U. S. Engineers, was the senior engineer of this army until October, 1864, but in consequence of his illness, in August, the duties of his office devolved upon General Michie.

July. – No engineering operations of any importance were carried on during this month.  Attention was principally directed to strengthening the lines already laid out, in building water batteries for 100-pounder guns for the defense of Trent’s Reach, and in general repairs to the line.  During this month there was constant picket firing all along the front, constant surprises on the part of both forces of the picket-lines, and attempts to gain ground toward each other.

A signal tower 120 feet high was built at Point of Rocks, from the top of which could be seen the Richmond and Petersburg Railroad and turnpike.  This gave us the means of obtaining a great deal of information, and must have impressed the enemy with this idea, for they established a casemated battery of three Whitworth rifled field guns for the special purpose of firing at this tower. But one shot of all fired at it struck it, and that only splintered one of the posts without damaging the tower itself.

August. – On the 3d of August a pontoon bridge 560 feet long was built on the Appomattox River at Broadway Landing for the passage of the Second Army Corps.

A second signal tower 126 feet high, and capable of being made 40 feet higher, was built on the right flank of the line, on the high bluff known as Crows Nest, James River, opposite Aiken’s.  From the top of this could be seen the Richmond and Petersburg turnpike and the cross-roads connecting the main roads which ran to Richmond on the north side of the James River.  A lookout constantly stationed here gave information of the enemy’s movements.

Major-General Butler having conceived the idea of cutting a canal across the peninsula known as Dutch Gap, to pass iron-clads and other war vessels through to avoid Trent’s Reach and the Howlett Battery, and the idea receiving the warm support of the then commander of the navy in the river, a survey of the locality was made by his direction.

From the sketch given below it will be seen that the river widens from 400 feet at the Howlett house to 2,700 at Trent’s Reach.  As a consequence, at the latter place the channel becomes narrower and shallower, and at ordinary high water vessels drawing twelve feet ten inches of water can pass under favorable circumstances, but the channel was effectually blocked by the powerful battery (Dantzler) at the Howlett house, which had a plunging fire upon the whole channel from Trent’s Reach up to within a few hundred yards of the Howlett house.  This battery had also embrasures cut to look up the river, to give a fire in rear in case any vessel was successful in passing the heavy fire of its front.

The survey of Dutch Gap showed a center section line 522 feet long, from a point in the channel on the south to a point in the channel on the north, 15 feet deep.  The highest point on this center line was 38.5 feet above high-water mark, and the lowest 4 feet, which was at the south mouth.  On a line 60 feet from this center line, on either side, the ground rose to 42.8 feet at the north mouth, and to 11.4 feet on the south.  The difference of water level was 10.1 inches, taken at extreme low tide, thus showing the natural fall of the river between these points to be 2.13 inches to the mile.  To all appearances the soil offered no insuperable difficulties for excavation, although it was rumored that the James River granite, which outcropped a mile above the lower mouth and a mile and a half below, would be met with beneath the upper strata and cause a complete failure.

The strata met with were as follows, viz: Yellow Virginia brick clay for twelve feet; layer of coarse sand and gravel, two to four feet; half an inch to two inches bog-iron ore; layer of pebbles and large gravel, two feet; then hard blue clay, or hardpan, containing a large quantity of sulphuret of iron or iron pyrites.  This latter stratum was never exhausted, and the bottom and sides of the canal were chiseled out of this, presenting as smooth and compact a surface as if built with masonry.  In round numbers, there were about 48,000 cubic yards to be excavated – the canal to be sixty feet wide at high water, forty feet wide at bottom, and fifteen feet deep.

It is a question whether this project – one of the simplest in civil engineering – would have been of any advantage other than to bring our navy a few miles farther up the river; for after it was commenced it was well known that other and nearly as powerful batteries lined both banks of the James River, commanding almost impassable obstacles, and ready to do their share in disputing the passage to the rebel capital.  And besides, it was an ascertained fact that the river was filled with torpedoes of the most delicate construction, most painful evidence of which we had in the destruction of three of our vessels in reaching the position then occupied.  If any advantage could have accrued to us from this canal in a military point of view, it would be a maximum only by keeping it a profound secret.

The excavation being ordered to proceed, ground was broken on the 9th of August, and immediately thereafter the enemy began the constant annoyance with their rifle and mortar batteries, which ended only with the suspension of labor on the canal, January 1, 1863.  There were thrown in the vicinity of the working parties over 20,000 shells during the whole period of the work.  The canal was excavated mainly by soldiers and partly by dredges.  The latter were old and almost worn out, and were worked by civilians, who did not come up to their promises, being driven off and frightened by the enemy’s shells.  Not more than 6,000 to 7,000 cubic yards were removed by the dredges, which were promised to remove 400 cubic yards every ten hours.  They worked from the south mouth 200 feet up into the canal, where an embankment separated the part on which the soldiers were working from the lower half.

The whole canal, except an embankment at the north mouth to protect against direct firing, was excavated to the required dimensions.  The soil was very favorable below high-water mark.  It was the “hard-pan” of miners – a hard, stiff, blue clay, perfectly impervious to and insoluble in water.  Whatever leakage took place through the strata of sand and gravel was removed by a steam pump.

About the middle of December the mines which had been made in the embankment were nearly completed.  This embankment was much larger than was intended to be blown out with powder, for it had been General Michie’s endeavor to reduce it far below what would have been almost certain to be removed, but during his absence the water had been let into the excavated part and up to the embankment without orders.  It would have required a greater amount of labor and length of time to remove it than we were warranted to use at this period.

It remained then only to do the best to blow out the mass between the water in the river and that in the canal; and the problem became to use an amount of powder large enough to remove the embankment and disturb its foundation so that it would be easy to remove afterward and, at the same time, not so much as to disturb and cave down the walls of the canal in the vicinity.  Twelve thousand pounds of powder were divided among five mines – one of 4,000 and four of 2,000 each – distributed as follows: Three mines were placed at a depth of fifteen feet below high water, one of 4,000 being on the center line of the canal and thirty-five feet from the face of the embankment, and two of 2,000 each were placed on the same level ten feet on each side of the center line and twenty-five feet from the face.  Two remaining were at a depth of twenty-five feet below high-water mark, or ten feet lower than the three first, and twenty feet farther out than the central mine toward the channel on the north side.

Toward the time of charging and tamping the mines the water leaked in very rapidly and the pumps were kept going night and day. The powder in the four smaller mines was in tin cans holding 125 pounds each.  In the larger mine the powder was in four large rubber bags holding 800 pounds, all opening into a water-tight box which contained 800 pounds, and in the center of which was the point of fusion of this mine.

The method of exploding the mines was by means of the Gomez fuse, a quick-burning composition said to be instantaneous for distances under 100 feet.  This method proved defective, and the results showed conclusively that all of the powder did not burn, and will not when ignited in the center of large mines. The effect would, in General Michie’s opinion, have been several times greater if centers of fusion could have been made for every hundred pounds of powder, which can be done now with an electric apparatus.

In the method used, in the center of each charge was placed the end of a length of Gomez fuse, cut at different points to allow the flame to ignite the powder in several places.  This fuse was then grafted to an equal length in the same level running to the other mine.  The three mines in the upper level were joined in the same way and, finally, the two lines were grafted together and joined to the end of a piece of slow-match cut to burn twenty minutes.  The grafts had been tried repeatedly before being finally determined on, and had always been successful.

On exploding the mine the embankment was thrown down and a current commenced running through the canal.  Excavation by means of discharging cans of powder under water deepened and widened the channel, aided by strong freshets, so that at high water six and a half feet of water is on the embankment.  General Butler having been relieved from the department about this time, work was discontinued by order.

The canal at present is used by the steamer O. S. Pierce and others of that class, which save by this way about five miles and a half of travel.  A few days work to clear up the disturbed mass and to widen and deepen the north mouth would make this the usual traveled route by all vessels navigating the river.  The current and tide partly flow through this way, but their action is unimportant in clearing it out, because the debris consists of large lumps of cemented gravel and hard blue clay.  The above embraces all the data of interest in this much-talked-of project, and is given complete to avoid referring to it in the account of each months labor.

September. – During this month a line of works was built and a post established at Harrison’s Landing.  The defensive works consisted of a redoubt of four embrasures, with a stockaded gorge commanded by the gun-boats in the river, and infantry breast-works running from the flanks to the river.  The length of the whole line is 1,412 yards.  A canvas pontoon bridge of twenty-three boats was built on the Appomattox River September 19.  The pontoniers who built it, having no experience with these boats, were twelve minutes in building the first and three minutes in building the last, the average time being seven minutes and a half for each boat.  Owing to the river being affected by the tide, the claw balks had to be lashed to the saddle piece, or they would slip up or down, according as the tide was ebb or flow.  Often this bridge had to be covered with manure to deaden the sound of travel when troops crossed.  In these cases the dust of the manure falling into the canvas boats would rot the threads of the canvas and cause more or less leakage.  It was noticed that some of the canvas coverings would leak as much as six inches of water at night and none the following day.  Teams heavily loaded would often sink these boats to within four inches of the gunwale. These were among the most prominent things noticed in the use of these boats in a permanent bridge, a use, however, for which they were never intended.

During the night of September 28 a pontoon bridge 1,320 feet long was built on the James River at Aiken’s Landing.  With 100 pontoniers the bridge was finished in six and a half hours, so quietly as not to disturb the enemy’s pickets on the opposite side of the river.

The army began to cross at 3 a. m. September 29 in two columns, one on the bridge above spoken of and the other on the bridge at Deep Bottom.  A successful advance was made; Fort Harrison, the key point of the outer line of Richmond defense, carried by assault, and the line of works extending to the Darbytown road occupied by our army. It having been determined to remain in the position thus carried, the rebel works from Fort Harrison to the New Market road were occupied by our troops and their front turned during the night and following day.  Shortly afterward a line was thrown up, with batteries at appropriate intervals, extending from our left flank, at Fort Harrison, to the James River, where it rested on a large work at a point a little above Cox’s Landing.  This work, called Fort Brady, was on the site on which the rebels had commenced the erection of a powerful rifled battery to command the mouth of the canal.  We armed the work with three 100-pounder Parrott guns and several 4 1/2-inch Rodman rifles, constructed a large bomb proof for the protection of the garrison, and surrounded it by strong lines of abatis.  The line from this work to Fort Harrison afforded a secure defense in case of a flank attack on the left, as it subjected the attacking party to a chance of being defeated, cut off, and captured, or driven into the river, after leaving their own lines.

October. – Efforts were early made to strengthen the right flank by a strong line and redoubts, but the work was stopped by order from the then commander of the Tenth Army Corps.  A strong attack on this flank was made by the enemy in force on the 7th of October, which the cavalry who guarded this flank were unable to withstand, and which at one time threatened to be very disastrous to this army.

Terry’s division, of this corps, with the artillery under Jackson, checked and finally drove back the enemy, and then the work of securing the flank was pushed rapidly along.

About 400 yards east of the New Market road a strong redoubt fifty yards square was built, and formed a salient from which the whole country within 600 yards was commanded, and from its right flank an infantry parapet of strong profile, well protected from assault by abatis, ran toward the New Market road, where it rested, about the vicinity of the Four-Mile Church. From this point to near the mouth of Four-Mile Creek strong isolated redoubts were built and manned with troops and artillery, so placed as to mutually support each other.  Along New Market Heights the most salient points were taken and occupied by strong closed works, and in their front for 1,000 and 1,500 yards the woods were slashed, thus making a continuous abatis in their front to the limit of the range of their artillery.  Works were also placed to flank the valleys and sides of these hills.

As there was some possibility of moving the greater part of this army to a new field of operations, leaving but a small force behind, a line of interior works, some 3,400 yards long, was built but for such a contingency.  The right rested on Four-Mile Creek, and the left on the marsh below Aiken’s Landing.  The details of construction were the same as generally belong to field defenses, the stronger batteries being placed so as to command the most important roads or the most probable points from which an attack would be made, with infantry parapets four to six feet thick on top joining them.

In front were ditches from eight to twelve feet wide and six feet deep, and in advance of these a line of good abatis.  This line was well indicated, the batteries completed, and infantry parapet two-thirds finished, the remaining work to be done after the troops occupied the line.  Often the greatest difficulty has been in getting an army to take up a proper and exact line of defense at first, each regiment, company, and man digging where they find their spades, without reference to the fitness of things, indicating the necessity of more engineer officers.

As detached works to this line, it was intended to hold those on New Market Heights and Camp Holly, which would have given us the command of New Market, Kingsland, and Darbytown roads.  The necessity for this line never occurring, it was never occupied by troops.

After the occupation of Fort Harrison and the rebel captured lines, the enemy began the construction of a new line of defense joining their water batteries on the river at Chaffin’s farm with Fort Gilmer, and running thence easterly to join on to that portion of the captured line which we could not occupy at the Charles City road, and so on to New Bridge on the Chickahominy.

The line that our forces occupied was made as strong as possible, and possessed the advantage of having but a short part exposed to an attack of the enemy, which part was strongly manned and guarded.

On the 27th a movement was made on the Darbytown and Williamsburg roads with no other result than to keep the enemy from sending re-enforcements to the right of their army at Petersburg, which was then being attacked by the Army of the Potomac. During this movement General Weitzel’s troops fought on the same ground in advance of Seven Pines on which the Army of the Potomac fought in 1862.

November. – Details of both engineers and infantry were constantly employed during this month in repairing the works of defense and perfecting and completing those alluded to.  During this season the roads used by the supply trains from the wharves and bridges became much cut up, and corduroying was commenced.  Wharves for the quartermaster, ordnance, commissary, and medical departments were built at suitable places on the river.  Frequent rumors arriving at Fort Harrison that the enemy were mining the work, in order to allay the fears of the garrison well holes were dug on the glacis to serve for listening galleries.  As the nearest approach of the rebel works was 800 yards, and a valley twenty feet deep had to be crossed before reaching the work, but little attention was paid to these rumors.

While attention was paid to the defensive operations we also found time to collect, repair, and put in working order three saw-mills, which were located in a splendid forest in the Bermuda woods.  By these mills from 7,000 to 10,000 feet of lumber were sawed per day, the greater portion of which was used in the construction of a permanent hospital at Point of Rocks.  Sufficient was obtained, however, to stock the engineer depot and build platforms and magazines in all the batteries, wharves, and bridges on the river.

Below is a report of the engineer force of the army, and how employed, which may be taken as a fair standard of each days detail during the period of quiet:

Two officers, 80 men, building redoubts and corduroying roads; 2 officers, 66 men, repairing Tenth Army Corps front; 2 officers, 90 men, repairing Eighteenth Army Corps front; 1 officer, 30 men, bomb proof to dredge Dutch Gap and Fort Brady; 1 officer, 50 men, corduroying roads; 2 officers, 30 men, engineer depots at Bermuda and Fortress Monroe; 2 officers, 143 men, various small details, & c. – 12 officers, 489 men.  First New York Volunteer Engineers – four officers, 105 men, on duty at saw-mills, building wharf, pontoon bridges, repairing wagons, & c.

December. – This months labor was a continuation of the last, and the principal roads of supply were ready for winter use quite early in the month.  Whatever damages had been done to the defenses were repaired.  Timber for a permanent pile bridge was prepared in the woods, which bridge was to be built in January.  A detachment of engineer troops accompanied the expeditionary force to Fort Fisher.

January. – As the enemy frequently opened a heavy mortar fire from in front of his works opposite Fort Harrison, and as the artillerymen were unable to stand to their guns during its continuance, it was deemed advisable to make protection to the guns on the front of Fort Harrison.  The mortars used by the enemy were Coehorns, placed outside of their works and behind the line of picket reserves, protected in their front by a strong line of abatis.  It was designed to bomb proof the whole front of the work and put in casemates enough, constructed somewhat on the Hoxo plan, for the guns on the front.  There was a banquette for infantry on top, reached by broad, wide stairs in rear, which gave the infantry good cover and enabled them to see perfectly every point in advance. The ditch was deepened and widened and a fraise placed in the scarp to prevent scaling.  But four of these casemates were constructed, and two bomb-proofs, a sketch of which is shown on the opposite page.

There were also three strong lines of abatis and wire entanglement placed in front of the ditch, making the whole work quite formidable and easy to hold.

In order to save sand-bags, which at this time became very expensive, Lieutenant King, Engineer Corps, designed some loop-holes for riflemen and for use in the picket-lines, which proved admirably well adapted for their purpose, and being prepared at slight cost at the saw-mills, were used on all the works and rifle-pits.  They were constructed of boards, and of the form shown in the diagram.  They presented a smaller target for the enemy’s sharpshooters and at the same time gave a large field of fire.  They were not easily discernible at any distance and could easily be removed and replaced.

Note. – The rebel device for the same purpose consisted in placing logs of various lengths, ten to fourteen inches in diameter, hewn on two sides, with notches cut in the lower side once in about six feet along the interior crest of the parapet, and banking these logs in front with earth.  The notches which formed the loop-holes were tapering toward the outside, similar to our own, and where there was much sharpshooting the orifice was still further reduced by a plate of thin boiler iron eight or ten inches square, with a hole in the center but little larger than the barrel of a musket.  These plates were spiked to the front side of the logs (covering the notches), and in some cases were found with fifteen to twenty bullet marks upon them, many of which were so near the edge of the opening that the bullets probably went through, and it is quite likely that all the bullets that struck the plate would have struck the man in the rear of it had ordinary sand-bag loop-holes been used.

The engineer may at times find this expedient worthy his attention, observing that the logs near the crest of the parapet are not suitable where artillery can be used against them.

The permanent pile bridge was finished after a little more than two weeks labor, being I ,368 feet long.  It became necessary as a substitute for the pontoon bridge owing to the great freshets in the river, the floating ice, and the driftwood that came down the river at this time.  It was a pile bridge, each pier consisting of three piles driven firmly into the bed of the river and connected by a cap piece, and the piers joined by strong pieces to form bays each fifteen feet wide.  An inclined log was attached to each pier to ward off drift and ice.

This was securely attached to a pile driven a short distance above and in the prolongation of the pier, which pile was nearly sawed off.  When driven by the pile-drivers sufficiently it was broken off, and the end of the inclined pile thus anchored to the bottom; the other was spiked to the pier, as shown in the sketch below.

The river deepens to 16 feet about 1,000 feet from the north shore, and then to 30 feet for a distance of nearly 180 feet, and then decreases rapidly to the shore-line.  At the channel a draw of pontoon-boats was made 180 feet wide.  The lumber which was used in the construction of this bridge was obtained from the engineer depot sawmills.

February.  There were additional river batteries on the south side of the James, constructed and armed with 100-pounder guns, as an additional protection against another rebel raid of iron-clads.  During this month and early in March the engineer force of the army decreased rapidly, owing to the expiration of their term of service.

March. – There were at this time less than 300 effective men for duty, and but a small number of these were engineer soldiers proper.  Repairs of the batteries were constantly going on.  To obviate the effects of winter weather, platforms were relaid, magazines drained, and their cover renewed and thickened, and generally the lines of the army put in good defensible condition.

The mules belonging to the pontoon train were worked continuously at the sawmills during the winter, and only relieved when directed by Major-General Barnard, the engineer of the combined armies operating against Richmond, to be used in preparing four pontoon trains for active service and marching.  New mules were obtained, and every effort made to break them to harness in time. The whole artisan force was put at work to repair and strengthen the wagons and boats.  Finally orders were issued to take a train of but fifteen canvas boats, which was ready for the march on the day specified.  The engineer force was divided; one part under Bvt. Maj. W. R. King, U. S. Engineers, remained with General Weitzel’s forces, and entered the city of Richmond with his command.  They began and continued the erection of a defensive line until the news of Lee’s surrender reached the city.  They also built a pontoon bridge joining Richmond and Manchester 2,400 feet long, upon which afterward the Armies of the James, the Potomac, Sherman’s army, and Sheridan’s cavalry crossed.  The engineer force with the moving column consisted of six companies of engineers and one of pontoniers.  A tool train of ten wagons moved with the pontoon trains; the latter consisted of thirty-two wagons, carrying forage, spare chess, and 380 feet of bridge material.  The weight, drawn by eight mules, was ascertained by weighing a pontoon wagon with its material two weeks after the campaign closed, and was found to be as follows:

During the march there were rains, which would increase the weight.  On the 29th of March the moving column of the Army of the James, consisting of Turner’s division of West Virginia troops, of the Twenty- fourth Army Corps, and Foster’s (First) division of the same corps, commanded by Major-General Gibbon, and Birney’s division of the Twenty-fifth Army Corps, all commanded by Major-General Ord, occupied the left of the Army of the Potomac, intrenched lines resting on Hatcher’s Run.

On the 30th an advance was made across the run by Turner’s and Foster’s divisions, rebel picket-line captured, and a position secured beyond Armstrong’s house, with 800 yards of the rebel line of works.  Turner’s division joined the Second Army Corps by a bridge built over the run.  On Turner’s right Foster and Birney made the connection with the Sixth Army Corps, still in position behind their intrenched lines.  Attempts were made during the night to build intrenchments and cover for a battery, but the ground would not stand, being saturated with water from recent heavy rains, and so spongy that it would not bear the weight of a horse.

April. – On the morning of the 2d, the successful assault being made and rapidly followed up by an attack on Fort Gregg, which was taken after some desperate fighting, the troops occupied a position entirely surrounding Petersburg.  During the night everything was got in readiness for a rapid march in the morning.  Starting at S a. in., and taking the Cox road, our army made a rapid march toward Burkeville; a part of the engineer force moved ahead to repair roads and bridges; the pontoon trains followed headquarters, to be in readiness in case of necessity.  Burkeville was reached on the night of the 5th and occupied during the next day.  A small force being sent out to burn the High Bridge at Farmville was met by the rebel advance and captured, after desperate fighting.  The troops moved in that direction on the 6th, and engaged a portion of the advance of the enemy, while the cavalry headed them off on the Prince Edward Court-House road.  On the afternoon of the 7th the troops entered Farmville, the enemy burning the bridges at this place and retreating across the river.  The pontoon train of our army having been well kept up to the front, notwithstanding its overloaded condition, was fortunately able to be used to pass over the artillery and trains of the Sixth and Second Army Corps and enable them to follow in rapid pursuit of the enemy that night.  The pontoons were relieved by those of the Army of the Potomac before daybreak, and once more in position for a new march.

At daylight on the 8th the Twenty-fourth Army Corps moved from Farmville, taking the road running nearly with the South Side Railroad, and made a forced march of nearly thirty-three miles before midnight, resting for a few hours on the railroad where Sheridan had captured several cars loaded with bacon and corn.  At 3.30 a. m. on the 9th the infantry moved again, and at 8 a. m. were in action on the extreme left of the army.  The leading brigade of Foster’s division, of the Twenty-fourth Army Corps, went into action on the double-quick, and delivered the volley which staggered and drove back the advance of the enemy, who had at that moment gained some temporary advantage over the cavalry.  The action lasted until 10 a. in., when a truce was granted preliminary to the surrender.

May. – During this month a bridge was built at Fredericksburg.  Surveys were made, by direction of Major-General Barnard, of the detached works surrounding the city, and orders were afterward received to continue the survey of the intrenched lines and country adjacent to Richmond.

June. – Brevet Major King was intrusted with the charge of rebuilding a bridge, called Mayo’s Bridge, connecting Richmond and Manchester.  The following is an extract from his report on the completion of the bridge.  The plan adopted for the bridge is represented by the accompanying drawing, page 43 [195].

DESCRIPTION

c f i, main chords made of four pieces, four by twelve inches, breaking joints, and forming continuous beams the entire length of the bridge. j i, corbels, fourteen by sixteen inches, resting on wall plates w w, and supporting main chords. a b g h, & c., straining beams, ten by twelve inches, oak, supported by posts and struts.

b c g f, & c., main suspending rods in pairs, secured at b and g by wrought-iron plates, and at c and f by cast-iron connecting plates bolted to the chord.

c d and e f, lower suspending rods, secured at c and f to cast-iron connecting plates, and at d and e to horizontal wrought-iron bars; these bars being connected by three small rods d e, d k, and e k, diagonal iron braces, to prevent vertical undulations.

k k, floor girders, ten by fourteen inches, supporting 4-inch by 12-inch joists and 3-inch plank.

d k e k, oak supports, six by ten inches, resting in cast-iron shoes, which are supported by wrought-iron bars d and e.

Lateral braces (not shown in drawing) connect the floor girders to prevent horizontal swaying, and diagonal braces steady the posts d k and e k.

DIMENSIONS

Entire length, 1,396 feet; entire width, including sidewalks, 31 feet; width of carriage-way in clear, 19 1/2 feet; number of bays, 18; width of bays, 69 to 78 feet; height of piers at low water, 20 feet. The strains on the different rods were computed as follows: Allowing for a load of 40 pounds per square foot of roadway, 40 pounds per cubic foot of timber, and 60,000 pounds as the breaking weight of iron per square inch, then the greatest strain on the upper suspension rods will be nearly 32,500 pounds.

[OR Series 3 Vol. 5, pages 183 - 196]

We have added it here to improve the clarity of this report.

Please note that the information covers just May – June 1864, not the entire fiscal year.

Narrative collated from reports of Major Mendell

PONTOON TRAINS

The companies of the U. S. Engineer Battalion with the Army of the Potomac were under the immediate command of Major Mendell, of the Corps of Engineers, with Captain Turnbull, Lieutenants Mackenzie, Benyaurd, Howell, Cuyler, and Heap, whose services, with the men under their command, are given in Major Michler’s reports.

The pontoon trains for service in the field, and to accompany the several army corps, were under the command of Lieutenant-Colonel Spaulding, of the Fiftieth New York Volunteers.  The services rendered by this branch of the Engineer Department were indispensable to the success of the army.  Without these transportable bridges the armies could not have moved through a country intersected with numerous rivers, wide and deep, and oftentimes with rapid currents, as well as ebb and flood tides.  The material of this branch of our service is modeled from the French wooden trains and the Russian canvas trains.  These trains, particularly that with light canvas boats, have, during this war, for the first time been proved advantageous and efficient and adapted to our country. They have been very generally used by the armies in the West and South, as well as the armies in the East.  The officers having charge of these trains and their construction have devised and adopted many useful modifications in the details.  Lieutenant-Colonel Spaulding has added much to these modified improvements.  The accompanying tabular statement from his report will exemplify the use and value of this indispensable branch of the engineer service.

From the above statement it appears that the total number of pontoon bridges built was thirty-eight, and their aggregate length 6,458 feet.

During the whole time covered by this report he believes the pontoon trains have been promptly on time when ordered, the bridges rapidly and skillfully built, and all other engineering operations of the command faithfully performed.

Whatever credit may be awarded to this is mainly due to the energy and skill of the officers in immediate charge of the several works, and to the zealous and faithful co-operation of the men under their command.

[OR Series 3 Vol. 5 pages 182 - 183]

Upon the explosion of the mine [July 30, 1864] and failure of the assault the troops engaged were directed on the following day to resume their previous positions to a great extent, some few changes being ordered for the purpose of reducing their fronts and establishing reserves for ulterior movements.  The plan of the siege by regular approaches having been abandoned, Colonel Michler was directed at the same time to make such a disposition of the lines then occupied by the corps as would enable them to be held by a diminished force, and therefore determined to select an interior line, to consist of some few detached, inclosed works, subsequently to be connected by lines of infantry parapets.  The first line selected was one lying on very commanding ground, and extending from the present Fort Sedgwick to the Rushmore house, immediately opposite Fort Clifton, one of the enemy’s works on the Appomattox, at the head of navigation for large sea-going vessels, passing near the Avery, Friend, Dunn, and Jordan houses. This being considered too far to the rear of the then advanced position, and apparently yielding too much ground, for the possession of which such desperate fighting had taken place, he finally chose an intermediate one, and sites for Forts Rice, Meikel, Morton, Haskell, Stedman, and McGilvery were selected, and the intervening batteries and lines located.  It had also been decided to enlarge and strengthen the lunette, the site of which is now occupied by Fort Sedgwick. By direction of Lieutenant-General Grant the supervision of the line in front of the Eighteenth Corps had also been placed under his direction.  The construction of these different works was pushed rapidly forward by night, under the immediate charge of Captains Gillespie and Harwood and Lieutenants Howell, Benyaurd, and Lydecker, as much so as the sparsity of officers, the extreme heat of the weather, and the heavy and constant artillery fire of the enemy would permit.

Several officers of the Corps of Engineers, including Captains Mendell, Turnbull, and Farquhar, had been ordered away from the army on other duty, and some of the lieutenants were absent on sick leave.  By the 20th of August the works were so near completion as to be in readiness for the contemplated movement on the Petersburg and Weldon Railroad.  After the successful advance and holding of that most important thoroughfare he was directed to select positions for large works on or near that road for the protection of the left flank of the army, and also to connect them, by a system of redoubts, with Fort Sedgwick.  On the 26th of August, in connection with the disposition of troops then made, orders were given him to proceed at once to the construction of the redoubts proposed for the left of the line on the Weldon railroad, and of the works at the Burnt chimney and the Strong house, now designated Forts Dushane, Wadsworth, Howard, and Alexander Hays.

The construction of these works and intermediate batteries, connected by infantry parapets, was immediately commenced, under the more immediate charge of Lieutenants Howell, Benyaurd, and Lydecker, and was afterward turned over to Captains Folwell and McDonald, Fiftieth New York Volunteer Engineers.  Owing to the bad condition of the roads during the late move, the commanding general directed that a line should be selected for a military railroad from the depot at City Point to the intersection of the Weldon railroad, at or near the Yellow Tavern, for the more certain and rapid transportation of supplies.  The laying of this road was placed in charge of the construction corps of the chief quartermaster of the Armies operating against Richmond.  The soil contains a great quantity of sand, and at times becomes almost impassable.

By the 7th of September the interior portions of the works last referred to were well advanced, sufficiently so to be occupied in case of an attack by the enemy, and obstructions, consisting of wire entanglements, abatis, fraises, and slashing generally of the timber along the entire front, had been prepared.  Many miles of corduroy roads and bridges had been built by the Fiftieth New York Volunteer Engineers for the convenience of and more direct communication between the different corps of the army.

During the first few days of September he also selected sites for different works, and traced a line from the bastion works (Fort Dushane) on the Weldon railroad to the rear of the camps of the armies operating against Petersburg, its left resting on the Blackwater Swamp, near Fort Bross.  These were designed to guard against any movement of the enemy on the three large and important thoroughfares – the Jerusalem plank, the Norfolk stage, and Halifax roads.  The several redoubts then laid out and commenced were subsequently named Davison, McMahon, Stevenson, Blaisdell, and Kelly.

In his report for the week ending on the 17th of September he reported that along every portion of the line, from the Appomattox River, below Petersburg, to the Weldon railroad, and thence back to the Blackwater Swamp, work was progressing rapidly.  The length of the line at that time was over sixteen miles, and along it had been constructed, or were in course of construction, nineteen forts and redoubts and forty-one batteries.  In addition to the labor on these works, including the obstructions in their front, bombproofs, magazines, and drainage in the interior, nearly 2,000 yards of roads and one-third of the covered ways had been corduroyed, and 6,700 square feet of substantial bridging built.  The old intrenched lines were also being leveled.  These labors were continued during the following week, the officers and men of the regular battalion of engineers and of the Fiftieth New York Volunteer Engineers having the construction of them.  At the same time his attention, under instructions from the commanding general, was directed to the examination of the country in reference to a defensive line from Blackwater Swamp, near Prince George Court-House, north toward Old Court- House, on Baileys Creek, the latter a deep, impassable stream, emptying within a few miles of that point into the James River.

This line, in connection with that already in course of construction, completed the chain of works from the Appomattox, below Petersburg, to the Weldon railroad, and thence back to the James River, adding nine miles to its length, making twenty-five miles in all, the flanks resting on the two rivers, and with them entirely encircling the Army of the Potomac. (See plan No. 12)

The sites of five works were traced, and work commenced upon three of them.  At the same time he was directed to confer with Lieutenant-Colonel Benham, Corps of Engineers (brigadier-general of volunteers), in command of the immediate defenses of City Point, in regard to a short line extending from the Court-House, on Baileys Creek, north toward the Appomattox, to cover and protect against any sudden attack of cavalry the depot at that point.

On the 21st a circular from headquarters Army of the Potomac directed that the armaments and garrisons designated for the forts be regarded as permanent, to be moved only when specially directed.  By the 26th the military railroad was completed, opened for travel, and placed in charge of the provost-marshal-general of the army.  On the 28th, in company with the chief of artillery, he made a general inspection of the whole line and found the work progressing most satisfactorily.  During the evening of the same day orders were issued for certain dispositions and arrangements of the troops to be made, and that the whole army should be in readiness to move before daylight on the following morning.  The corps commanders were directed to “hold in view the contingency of the withdrawal of their troops from the rifle-pits connecting the inclosed works, leaving the line from the Appomattox to Fort Davison to be held by the redoubts and inclosed batteries, and the further contingency of withdrawing entirely from the intrenchments”.

In consequence of this projected movement, instructions were immediately given to the officers of engineers to suspend all operations on the different field-works in course of construction, and to hold their commands and the pontoon trains in readiness to obey further instructions.

The active operations of the army were successfully advanced some few miles to the left or west of the Weldon railroad during the 29th and 30th of September and 1st and 2d of October, causing a corresponding extension of the lines.  On the morning of the latter, after the repulse of the enemy in his final attack, it having been determined to hold on to the position, he was ordered to select a new line to connect the advanced point near the Pegram house with Fort Wadsworth, and locate the necessary intermediate works. The tracing, profiling, and construction of them was immediately commenced.

Before daylight on the morning of the 4th, by direction of the commanding general, he made a reconnaissance for the purpose of selecting a line to be refused from the left flank toward the rear, and to be connected with Fort Dushane.  The sites of several new redoubts were established, the connecting lines traced, and with large details their construction immediately commenced.

By this extension to the west of the Weldon railroad eleven additional inclosed works – Keene, Urmston, Conahey, Fisher, Welch, Gregg, Cummings, Sampson, Emery, Siebert, and Clarke and several batteries were linked with the already formidable cordon that surrounded the army.  The length of this portion of the line is nearly seven miles, making a continuous stretch of twenty-three miles of earth-work from the right, on the Appomattox, to the left, on the Blackwater Swamp.  Adding to this the section from the latter to the James River, the line measures more than thirty-two miles, comprising thirty-six forts and fifty batteries.  In addition to these, there were eight other inclosed works along the inner line of the defense of City Point.

The incredibly short time in which those to the west of the Jerusalem plank road were built surprised the officers of our own army. The sites of the works were only selected on the 2d and 4th of the month; still, the weekly report of the 8th states that they were already nearly completed.  To the officers of the Corps of Engineers then present, under his orders – Harwood, Gillespie, Howell, Benyaurd, Lydecker, and Phillips and to those of the Fiftieth New York Volunteer Engineers, under the immediate command of Lieut. Col. I. Spaulding, and to the men of their respective detachments, must be given the credit for the immense amount of work accomplished.

The works were well constructed and finished, and the infantry parapets are as strong as they could be made to answer a useful purpose. The artificial strength of the line was to a great extent increased by the naturally strong position chosen to resist any attack or assault by the enemy.

On the 4th of the same month, notwithstanding the few officers of the corps that remained on duty, he was compelled to send Lieutenant Phillips to report to General Benham to assist in constructing the line in front of City Point; the latter was about three miles in length, comprising eight small redoubts.

On the 12th the commanding general directed Colonel Michler to make an examination of that part of the line extending between Forts Hays and Fisher, to ascertain whether said line could be shortened, and to furnish a written report for Lieutenant-General Grants information.  As no particular advantage could be gained and a considerable amount of work would be required, he reported unfavorably.

The weekly report dated October 22 informs the General-in-Chief that the whole line occupied by the Army of the Potomac was entirely constructed and in a defensible condition.  Some minor details still required attention.  Additional obstacles, palisades, and fraises in connection with the abatis and wire entanglements had been rapidly pushed forward every night to strengthen it.  In consequence of reports that the enemy were driving galleries at different points to undermine several works, he directed shafts to be sunk within them and listening galleries to be run out as precautionary measures, although no indications were found to exist after a most careful personal examination.

On the 16th, accompanied by Captain Gillespie and Lieutenant Benyaurd, he examined critically the ground between Fort McGilvery and a point opposite Fort Clifton, to ascertain the strength of the enemy’s position, and whether any new works were in course of construction, as well as to decide upon the possibility of forcing a passage of the river and severing his communication by rail with Richmond.

On the 20th, by direction of the commanding general, he visited City Point in company with the medical director of the army for the purpose of selecting the ground for a general field hospital.  An advantageous place was found on the bluff overlooking the James, between the railroad and Bailey’s Creek.  Besides the convenience of locality, it possessed the advantage of retirement and security, as well as that of health.  Fine springs burst forth here and there from the banks sufficient to supply every want.

The names of the different works of the line to the west of the Weldon railroad and of that in front of City Point were selected from among those of the many distinguished officers who were killed in action during the recent campaigns, nobly fighting their country’s battles, and so given in plan No. 12.

On the morning of the 24th of October two new redoubts were ordered to be thrown up at points he had previously selected, the one between the Norfolk road and the Avery house, the other near the Friend house, from both of which positions command was had over the main line of works.  These were sufficiently far advanced for the movement ordered to commence on the afternoon of the 26th.  The latter, in which the greater part of the army participated, continued through the 27th and 28th, extending west across Hatcher’s Run, and reaching along and south of it as far as the Boydton plank road where the latter crosses the stream at Burgess Mill.

During the afternoon of the last day the different commands returned to their old camps.  The engineer troops were then engaged along the entire line, in repairing damages, adding obstructions, driving galleries, and in every conceivable way rendering the line as strong as possible.

On the 7th of November he was directed by the major-general commanding the Army of the Potomac to furnish General Benham, commanding defenses of City Point, with the project of the line of intrenchments from Prince George Court-House to Old Court-House, and also to indicate what was necessary to be done to connect the right of that line with the rear intrenchments resting on the Blackwater.

In consequence of a contemplated movement he had been compelled to suspend work upon that section of the defensive line, and its construction was subsequently turned over to the above-named officer.

By the 12th of the same month, the lines being completed, both as regards their external and internal arrangements, the following extract from Special Orders, No. 306, headquarters Army of the Potomac, of the same date, was issued for the information of all concerned:

The attention of corps commanders is called to the necessity of preserving, in good order, the intrenchments front and rear, with the abatis, slashings, and other defenses.

The chief engineer officer will inspect the lines, both front and rear, from time to time, and report to these headquarters any failure to keep the same in good order, or any destruction of the defenses.

From this time forward the engineer troops were principally occupied during the winter in attending to the needed repairs of the forts and batteries, in keeping in order the several corduroy roads, in overhauling and placing in good condition the pontoon trains, in constructing huts for winter quarters, and in building stabling for the large number of animals required for the transportation of the tool and bridge trains.

The temporary quiet of the army was again interrupted for several days.  On the 6th of December, by direction of the commanding general, an engineer officer, with a battalion of engineer troops and 150 feet of canvas bridging, was directed to accompany the Fifth Corps during the movement of the latter south along the Weldon railroad, and subsequently all, both regular and volunteer, were called upon to be under arms to take part in the same operation.  Orders were issued at the same time that all camps located, as well as huts, corrals, or other structures erected in the vicinity of the lines of defense, either in front or rear, which, in the judgment of the engineer, interfered with the proper defense of the works, should be immediately removed.  Preparations were also made to move, if necessary, all surplus property and the sick in hospitals to within the lines of City Point.  Arrangements in regard to the further disposition of troops were directed in the event of a general move; those not previously designated for holding the intrenched lines to be formed into a movable column, under the immediate orders of the commanding officer of the Second Corps. All work not necessary for the defense of the position held by the army was suspended.  The movement had scarcely commenced when, in consequence of severe storms of rain, accompanied with sleet, the army was finally compelled to return to its old position, some considerable damage having been effected along the line of the railroad.

Comparative quiet again reigned throughout the army, with the exception of the attempt of the enemy’s iron-clads to come down the James River on the 24th of January, 1865, until the 4th of February, when a movement of the cavalry was ordered for the following day, to be supported by the Fifth and Second Corps.  The cavalry successfully captured a small train of the enemy on the Boydton plank road and entered Dinwiddie Court-House.  In consequence of the destruction of a bridge over Hatchers Run, the Fifth Corps was detained for several hours in crossing, and the former, not being supported, fell back.  A severe attack was made upon the Second Corps, but was repulsed, and little more was effected on that day.  On the following morning (6th) the Fifth Corps was ordered to pass the stream at the crossing on the Vaughan road and take up position to the left of the Second, the cavalry protecting its flank.

Some severe fighting took place during the day.  Early on the same morning he had been sent to select a line between Fort Sampson and Armstrong’s Mill, and choose sites for works to hold and command the crossing at the latter place and the one on the Vaughan road.  On the 7th orders were issued to intrench the line, but on the following day were so modified as to cause the line to be run direct from Fort Sampson to the Vaughan road crossing.  The length of this addition to the intrenched line is nearly four miles, making the front line from the Appomattox to Hatcher’s Run fifteen miles of continuous earthworks.  Heavy storms of rain and sleet again disturbed this movement.

With the exception of the attack on Fort Stedmnan on the 25th of March, and its temporary occupancy by the enemy, no event of importance occurred until the inauguration of the campaign on the 28th of the same month.  The distance from Battery No. 10, adjoining Fort Stedman, to the point of the enemy’s line (Colquitt’s salient), immediately opposite, is only 613 feet between the main works, the shortest distance between the two at any point, excepting at Elliott’s salient (the locality of the mine).  The picket-lines of the two armies were only 435 feet apart, those of the enemy only a few feet in front of his main works.  One of the advanced Union pickets was only separated 205 feet from his opposite neighbor, a narrow boyau [sic] leading to his pit from the main line.  Without the exercise of the most untiring vigilance on the part of the picket and the garrison, any sudden dash at the first early dawn of the morning might prove momentarily successful; but a position so well flanked by adjacent batteries, and commanded by others in its rear, proved so untenable as to cause the enemy to be most severely punished for his temerity, and to compel him to relinquish the object of an attack for which no reasonable explanation can be made.

Before proceeding further he calls attention to the topographical department of the Army of the Potomac.

Owing to the limited degree of information which could be obtained, either from published maps or inquiries made of the inhabitants – the latter generally being averse and in most cases unable from ignorance to impart it, even in relation to the particular localities in which they lived – his assistants had a laborious although an interesting duty.  They have not only been constantly engaged in following up every movement, and in most cases acting as guides to the different columns of troops, thereby obtaining a most reliable knowledge of the country by actual experience, but have been compelled to anticipate the geographical wants of a large army ever in motion by constant and careful researches.

In order to be able to furnish the necessary data upon which to base the different military combinations, and thereby being made responsible to a great extent for the information upon which the commanding general was able to hypothecate a reasonable degree of success in the execution of his plans, the department had necessarily to be ever active and always exact.

The Engineer Bureau has been furnished from time to time with the many maps supplied the officers of armies operating against Richmond and Petersburg, including those of the campaigns from the Rapidan to the Appomattox; that of the carefully surveyed plan of the lines occupied during the siege of Petersburg; the several sheets representing the country adjacent to the latter city, and also about Richmond, comprising the several lines of the enemy for the defense of the capital; and also copies of those prepared in anticipation, and upon which were based the movements which terminated so successfully and gloriously the last grand campaign of April, 1865.

On the 27th of March certain movements of the several corps of the Army of the Potomac were ordered to commence at an early hour of the 29th.  On the 28th the instructions of the previous day were somewhat modified, but at the appointed time the several columns were in motion.

A pontoon train accompanied the Fifth Corps to enable it to cross Hatcher’s Run, and subsequently remained there for the passage of the general trains.  The Second Corps, which had been replaced by a portion of the Twenty-fourth along the intrenched line heretofore occupied by it, crossed by the bridge on the Vaughan road.  The cavalry passed over by a bridge still farther down, at Malone’s Crossing, and moved toward Dinwiddie Court-House.

In gaining their position but little opposition was encountered; one division of the Fifth had a spirited engagement on the Quaker road, and handsomely repulsed the enemy.

On the 30th the Second and Fifth Corps advanced their lines to beyond the junction of the Quaker and Boydton plank roads, driving the enemy into his main works; the two lines were within easy artillery range; the right of the Second now rested on Hatcher’s Run, near the Crow house.  A division of the Twenty-fourth Corps crossed the run and connected the right of the Second with the tete-de-pont on the Vaughan road; both lines were intrenched.

During the night previous and throughout the whole of this day the rain poured down in torrents.  The roads had become impassable for wagons and artillery, and the engineer troops were engaged in corduroying them and in rebuilding bridges over Hatcher’s and Gravelly Runs.

The wagon train stuck fast in the mud.  The cavalry had to be sent back by divisions to the terminus of the military railroad to replenish their supplies of rations, the wagons not being able to come up to them.

During the night of the 30th the Second Corps extended its front to the left along the Boydton plank road, resting its flank on Gravelly Run.  On the morning of the following day an unsuccessful effort was made by the Fifth Corps to drive the enemy from the White Oak road; subsequently, upon being re-enforced, the attack was renewed and possession gained of that road.

Toward evening the cavalry had repulsed and held in check, in front of Dinwiddie Court-House, a superior force of the enemy. During the night of that day, the 31st, the Fifth Corps was sent to the assistance of the cavalry.  From the commencement of the movement he had accompanied the commanding general over different parts of the field, in readiness to execute such instructions as might be given, and on the 1st of April, by his direction, rode along and inspected the lines from Hatcher’s Run toward the west. The evening of that day witnessed a most brilliant engagement on the left, in which both the cavalry and the Fifth Corps participated, the enemy along that immediate front having been completely routed.

This glorious news was communicated throughout the army, and orders were issued that a simultaneous attack should be made at different points along the entire length of the intrenched line at 4 o’clock on the following morning.  The grand assault of the 2d of April was made, and the exterior line of the enemy’s works penetrated and possession gained of the larger portion of them.

The enemy having been pierced at his center and divided, one portion was driven within an interior line of works immediately encircling the city, and the other moved off from the White Oak along the Claiborne road, rapidly pursued by a division of the Second Corps.  The line of the army extended at noon of that day from the Appomattox, above Petersbnrg, to the Appomattox below, the two flanks resting on the river.

Colonel Michler was at that time ordered to rectify this line if necessary, and later in the day to select a site for a pontoon bridge across the river, and positions for batteries to command the crossing and protect passage of the army in the event of the retreat of the enemy.

Early on the morning of the 3d it was ascertained that the enemy had evacuated the city of Petersburg, and orders of march were immediately issued to the different corps to follow in pursuit.  The roads were found in wretched condition, and a great deal of corduroying and bridging had to be done.  About noon on the 5th he was ordered to proceed in advance of the Second and Sixth Corps to report to General Sheridan, who had arrived with the cavalry and Fifth Corps at Jetersville on the previous evening, to consult with him in regard to the position to be taken by the army in anticipation of an expected attack by the enemy, it being reported that his whole force was concentrating at Amelia Court-House.  His line of retreat toward Danville had been cut off, and it was presumed he would venture a heavy battle to regain it.  In company with the general he rode over the line, and by the direction of the general the troops were posted as they arrived.  A part of the line of battle had been previously intrenched, and work was commenced on other portions; the anticipated fight, however, did not take place.

On the following day (6th) the Army of the Potomac was put in motion in three parallel columns toward Amelia Court-House to attack the enemy, but the cavalry having early ascertained that he was endeavoring to escape by Deatonsville toward Farmville, the direction of the line of march was immediately changed; the Second moved directly on the former place and in a short time came upon and commenced a brisk skirmish with the retreating force and continued to drive him until night closed the operation; the Fifth Corps was shifted to the right flank and took the road to Paineville.

Colonel Michler was directed to report the change of movement and explain its object to the commanding officer of the Sixth Corps. His column was countermarched and thrown from the right to the left flank.  After retracing its steps through Jetersville and passing some two miles beyond the village, it left the main turnpike and followed a road which he had found leading toward the northwest, and by which the troops moving along it were absolutely certain of striking the flank of the retreating army.  The entire cavalry force was operating on the same flank.

By night the battle of Sailor’s Creek was fought, which will long be remembered as one of the most brilliant and successful affairs of the war.  It was, in fact, the last desperate engagement between these two armies.

On the 7th of April the pursuit was continued.  The enemy having succeeded in crossing the Appomattox at Farmville and High Bridge, he succeeded in destroying all the bridges at the former place, but failed in his efforts to damage the common road bridge at the latter crossing; three spans of the railroad bridge (Richmond and Danville road) were burnt; this structure is 2,400 feet long and 125 feet high. The enemy made some slight resistance at both these places and also on the Lynchburg plank road at a point about four miles beyond Farmville.

The naturally very strong position at High Bridge was rendered additionally so by several redoubts which had been built there sometime previous for the protection of the bridge against cavalry raids.

On the 8th the Second and Sixth Corps followed along the Stage road to Lynchburg, whilst the Fifth, Twenty-fourth, and Cavalry Corps pursued the one by Hampden Sidney College and Prospect Stations toward Appomattox Court-House.

During the day he returned to Farmville to hasten the construction of some additional pontoon bridges and rejoined the major-general commanding on the main road.  On the previous evening Lieutenant-General Grant had demanded the surrender of General Lee to avoid the further effusion of blood.  No skirmishing had taken place during the day, although the one army was close on the rear of the other.

About noon on the 9th, in consequence of the negotiations in regard to the surrender which were pending and exchanged under flags of truce between the generals commanding the respective armies, the advance of the Army of the Potomac, still engaged in pursuit, when within three miles of Appomattox Court-House was ordered to halt and await the issue of the proceedings.  The other column had, by rapid marching, succeeded in passing around and confronting the head of that of the enemy at the latter place.

The few hours of anxious suspense were happily compensated by the glorious tidings which were soon proclaimed throughout the army announcing the surrender of the Army of Northern Virginia. On the following day the army commenced a retrograde movement toward Burke’s Station, where it remained in camp until ordered to take up its final march toward Washington, D. C.

On the 14th of April Colonel Micliler was detached from the staff of the commanding general of the Army of the Potomac, and directed, in conformity with instructions from Lieutenant-General Grant, to proceed to Petersburg, in order to examine and direct military surveys of the respective intrenched positions held by the two opposing armies during the siege and prepare plans of the same, combined with a detailed and accurate topographical map of the adjacent country; also to assume charge of the surveys of the different battlefields and lines of operations from the James River to Appomattox Court-House.

By the 30th of June, the termination of the fiscal year for which this report is called, the field-work had been far advanced, but in consequence of the necessity of continuing during favorable weather the survey of the several hundred square miles through which it extends, little or no office duty was accomplished – only sufficient drawing to answer necessary purposes at the time; and consequently the maps at that time were not sufficiently far advanced, and could not exhibit the large amount and the nature of the work accomplished.

[OR Series 3 Vol. 5 pages 173 - 183]

As portions of this report present information which should be withheld from publication, it is recommended that such portions be not placed in the hands of the Public Printer. These portions are indicated by being furnished herewith in a special package.

DISTRIBUTION OF OFFICERS

The operations of the Engineer Department and its officers during the year ending June 30, 1864, have embraced most branches of the profession and extended through most States of the Union on the Atlantic, Gulf, Pacific, and lake frontiers, and armies in the field opposed to the rebels.

The corps consists at present of eighty-six officers of all grades.  Lieutenant-General Grant has had the services of twenty-one officers of the corps with the armies operating against Petersburg and Richmond.  They have been occupied incessantly in the construction of field fortifications, reconnoitering the enemy & positions, building pontoon bridges and maneuvering the bridge trains, making surveys of the country occupied by the armies and plans of the siege works before Petersburg, and serving on the staff of the lieutenant-general and other general officers of the Army of the Potomac and James Rivers.

Major-General Halleck has had the services of two field officers on his staff attending to all the engineering duties of his bureau, while another field officer of the corps has been charged continuously with the defense of Washington City, with the co-operation and occasional assistance of several others.

The army under General Hunter had one subaltern officer upon whom devolved the duty of constructing bridges and collecting topo- graphical information for the movement of the army in its march through the Valley of Virginia, thence to the Ohio and back to the valley.

The army under General Sherman has had nine field and subaltern officers assigned to it, who have labored continuously in the construction of defenses for the numerous bridges on the lines of railroad, in fortifying many strategic sites, besides cities and towns on the lines of communication, in making surveys, and reconnoitering expeditions to procure information of the strength and position of the enemy, and collect topographical data upon which to construct campaign maps and plans of the various sites occupied by the army, and in the service of the pontoon trains for bridging the water-courses.

The army under General Banks had six officers attached to it, who constructed many field-works for the defense of particular localities, and under General Canby four officers, who conducted all the siege operations that ended in the capture of the permanent sea-coast defenses on Mobile Point and Dauphin Island.

General Steele has had two officers accompanying his army in its march through Little Rock to the Red River and back to Little Rock, calling for frequent use of the pontoon bridge trains in their charge and the construction of some field-works for the defense of particular strategic points.

The Department of the South, under Generals Gillmore and Foster, has had the services of three officers, who were most arduously engaged in the siege operations at Forts Gregg and Wagner, and in the demolition of Fort Sumter; and the Department of Virginia and North Carolina, under Generals Foster and Butler, has had the services of two officers, constructing the defenses of New Berne and Washington, N. C.

Such has been the disposition of the officers and their labors in their legitimate staff duties in the field.  These several armies have also no less than nineteen engineer officers as commanders of troops, aides-de-camp, and assistant adjutants-general, holding rank as major-generals, brigadier-generals, and staff officers.

While these field duties have been performed by engineer officers, twenty-four others have been engaged in the construction of the permanent and temporary sea-coast defenses on the Atlantic, Gulf, Pacific, and lake coasts.  Their labors have been arduous and unremitted, being necessarily compelled to superintend works so distant from each other that they were able to give but partial personal attention to any one.

The survey of the lakes has also progressed under charge of one officer, and the harbors on the lakes and Atlantic under another.  The selection of a naval site on the Western waters is assigned to another, as member of a commission for that purpose, and two others are associated with the chief engineer in the various duties of the bureau, where many of the maps are compiled for the armies in the field.

During the year nine officers of the corps have been lost by death, all of whom have given their lives to the service of the country . The whole Army mourns the loss, among these, of the distinguished chief who for more than twenty-five years so worthily commanded the corps.

EXPENDITURES, ETC.

The total amount expended by the department for the year is $6,345,191.74.  The amount appropriated by Congress for the prose- cution of the works on which this sum has been expended, including the Military Academy, is $6,959,297.  The number of sheets of maps furnished during the year by the topographical branch of the department to the armies in the field throughout the United States was 20,938.  Of sheets of the lake surveys, for commercial as well as military purposes and harbor improvements, there were distributed 3,688 sheets; making a total issue of 24,626 sheets.  For these supplies and for the instruments used in conducting operations to obtain these results, there has been expended the sum of $49,755. 81.

OPERATIONS OF THE YEAR

The expenditure for carrying on the war has been of first necessity, and the appropriations heretofore have in general absorbed the full amounts, while for permanent defense of the sea-coast a large amount remains unexpended and available for the future.

The work done on the several forts and batteries is particularized in the accompanying statement, as derived from the reports of the superintending engineer.d The great end in view has been to hasten to completion such parts of the works as would soonest enable the armaments to be introduced, and the progress made continues to be for all description of guns greatly in advance of the ability of the Ordnance Department to provide the required artillery while arduously engaged in providing the armies in the field with their necessary munitions.

The Board ordered by you in January, 1864, to examine the system of our sea-coast defenses as then being constructed, & c., entered upon its duties and proposed several modifications called for by the introduction of increased calibers in guns, the rifling of heavy artillery, and the use of armor-clad vessels as combatants.

Earth as an opposing mass to resist artillery, while it is also used to cover and protect masonry, has from the earliest period of permanent fortifications been considered the most reliable material and least subject to injury from an enemys artillery, whether large or small, rifled or smooth-bore, and all exposed masonry has been and continues to be objectionable as liable to certain demolition where fixed batteries of sufficient power can be brought to act against it.  These views the Board emphatically recommend to be steadily kept in view, and point out several instances where masonry parapets have been designed for works in progress where these can and should be substituted by earthen ones.

The Board was dissolved by its members being called into the field before time had been given for maturing detailed special plans for carrying their ideas into effect for the several works indicated for modification.  The several superintending resident engineers have been called upon for designs to modify their respective works so far as their present condition will permit, while in other cases special boards will have to be organized to mature detailed plans for the proper modifications.  The great pressure for engineer officers with the armies is now such that the requisite experience cannot be commanded for the organization of such board.

For the defenses of the California coast and to carry into effect the intention of Congress in fortifying the land approaches to San Francisco, a special board has been ordered and is now engaged on that duty, keeping at the same time in view the recommendations of the late Board created by your order of the 27th of January, 1864.

All the supplies of engineer niaterial required for our great armies in the field, whether of bridge equipage, supplies for siege operations, or for the construction of field-works and defensive lines, have been provided and distributed promptly as called for.  The principal depots for these supplies have been that of Washington, in charge of Col. W. H. Pettes, New York Volunteer Engineers, for the armies operating in this vicinity; the depot at Cincinnati, in charge of Lieut. Col. James H. Simpson, Corps of Engineers, for the Western armies, and that at New York for the general service, in charge of Mr. W. P. Trowbridge, engineer agent, who has also met all the calls for material, apparatus, & c., of the officers engaged in the construction of our permanent fortifications.

From among the reports from officers of the Corps of Engineers with the armies in the field I have selected five of particular interest that may be published at this time without prejudice to the public interest. They are -

First – On the use of india-rubber pontoon bridges by the army under General Steele.

Second – Passage of the James River by the army under General Grant on a pontoon bridge.

Third – Siege of Fort Morgan by the army under General Canby.

Fourth – Siege of Fort Gaines by the army under General Canby.

Fifth – Description of the mine made under the enemy’s works at Petersburg by the army under General Grant.

The journal of the siege of Forts Wagner and Gregg and the demolition of Fort Sumter will not be received in time to accompany this report.

Pontoon bridge – Passage of James River by the army under General Grant

HEADQUARTERS ENGINEER BRIGADE

Camp at City Point, Va., June 24, 1864

General R. DELAFIELD,

Chief of Engineers:

SIR: I have the honor to report, as you will see by the inclosed copy of note from Lieutenant Carroll, at the engineer depot, that the two wooden pontoons which you desired to have made according to my proposed modification are now complete at the depot and appear to be very satisfactory indeed.

Should you have the time I shall hope that you will be able to examine them soon, and if they please you that you will order all wooden pontoons in the future to be built of that model.  It is barely possible I have thought that it may be expedient to set the hooks for lashings some three inches more toward the stern to insure somewhat greater buoyancy at the bow.

I presume you will be pleased to hear of the success of our pontoon bridge, over 2,000 feet long, over the James River just above Fort Powhatan, which I had placed there on the evening of the 15th instant by the troops under Captain Mendell and Lieutenant Gillespie, of our corps, about 200 men, and two companies of the Fifteenth New York Volunteer Engineers, under Captains Lubey and Henderson, and a fractional company of the Fiftieth New York Engineers, under Captain Robbins, 250 volunteers, or, in all, 450 men.

n the 13th and 14th, in accordance with an order of General Grant I had sent up the pontoon rafts from Fort Monroe under the above-named volunteer troops, not feeling then at liberty from the previous orders of General Meade to leave my other property and troops to go up myself.  But about 11 a. m. on the 15th I received the order, and was under way in half an hour, arriving at the position selected at about 5 p. m.  There I found General Meade and General Weitzel, which latter had prepared the approaches and had the abutment commenced.  I was at once directly charged with the laying of the bridge by General Meade, with the regulars to assist the volunteers, and he smiled when I told him I should not sleep till the bridge was laid.

I distributed my men at once, the regulars at the east end, the volunteers at the west end, and a company of volunteers to prepare a part or raft by my plan of simultaneous bays.  At about 10.30 p. m. I received a dispatch from General Meade asking the progress of the bridge, to which I was able to reply at once that the last boat was in position, and the raft of three boats built ready to close the gap he had ordered left for the present, and that it was ready for completion in fifteen minutes at any time he ordered.

The gap was closed, but the bridge was not required or used until 6 a. m. the next morning, when the regulars were relieved and the bridge continued under my care with the volunteers, who carefully watched and repaired it every hour or oftener for the seventy-five or eighty hours it was down.  For the next forty hours after 6 a. m. of the 16th a continuous stream of wagons passed over the bridge (from 4,000 to 6,000 wagons) some said fifty miles of wagons and nearly all the artillery of this army, and by far the larger portion of the infantry and all its cavalry present, and even to its head of 3,000 or more of beef-cattle (the most injurious of all), without any accident to man or beast.

My officers and men were scarcely allowed any sleep during this time, nor myself as much even as four hours in the eighty hours preceding the taking up of the bridge, for it was in anxiety, not to say trembling, that I saw the destinies of this whole army of our country even committed to this single, frail, boat bridge, with steamers and other vessels drifting against it, and with much of its planking previously worn almost entirely through by careless use upon the Rappahannock, and I dared not stop the living stream of men and matter to sheath or protect it.

At length by 7 p.m. on the 18th the last animals were over and I breathed free again, and although the shelling of our troops across the river just before sunset within a mile above us gave us little hope of withdrawing the bridge in safety, it was ordered up and all rafted into three several tows before 3 a. m. of the 19th, and on its way to this point, which it reached about sunrise, the most successful effort on a large scale with pontoon bridging that has ever occurred in our country, if it does not rival those in any other land.

The bridge built over the Chickahominy by this same brigade about two years since was nearly as long as this, but built over a comparatively quiet and shallow stream at least for nearly its whole extent and with a great portion on trestles, and it was for but a small portion or one or two corps only of McClellan’s army, while this bridge, besides some 200 feet of trestle-work, was for over 2,000 feet in pontoons, and for the greater part of the distance in deep water, in some parts up to eighty-five feet, with a very strong current running for a great part of the time, and it transported nearly all the material, artillery, and trains with the greater portion of the men of this large army.

You may be sure I was very well content and satisfied and felt like “him that putteth off his armor” when the affair was over.

 Very respectfully, your obedient servant,

 H. W. BENHAM, Lieutenant-Colonel of Engineers and Brigadier-General

MILITARY ACADEMY

The Military Academy has continued to fulfill the purposes for which it was created, by collecting and procuring from all nations the arts and sciences connected with the defense of our country, and imparting this knowledge, so far as it is applicable to our people, to the cadets enjoying the benefit of a military education at this national institute.

The arm of service at this time calling for special attention is the artillery, which is still undergoing great modifications both for land and sea-coast application.  The superintendent has asked an appropriation for this branch to enable him to lay before the student the various appliances that late wars have introduced, many of which serve to impart useful information, while numerous others are valuable in guarding us against the immense expense in attempting devices that have proved, on trial, to be failures – a degree of knowledge that is the saving of immense treasure if we profit by this experience.  I commend the subject to your most favorable consideration, with a belief that store-rooms for artillery and small-arms of all kinds have now become, more than ever, of immense importance to the military profession.

The examination of the cadets of the Academy was held, as usual, in the month of June.

Twenty-seven cadets were graduated and have entered the Army.

The report of the Board of Visitors who attended the examination has not yet been received at this Bureau.  A list of the officers of the institution is hereto appended.

FORTIFICATIONS

TEMPORARY SEA-COAST DEFENSES

In the preceding statements several cases have been mentioned of cities, towns, or positions that it has been found requisite to defend by temporary works against the possible attack of the cruisers of the insurgents, in anticipation of the period when, under ordinary circumstances, they would have been supplied with permanent defenses. A number of other cases of this kind will now be summarily specified: Eastport, Me., has been defended with two temporary batteries, mounting five guns each.  Machias Port, Me., has been defended with one temporary, of five guns . Castine, Me., has been defended by one battery of five guns.  Belfast, Me., is defended by two five-gun batteries.  Rockland, Me., is furnished with two five-gun batteries.  Newburyport, Mass., is supplied with one battery mounting nine guns.  Gloucester, Mass., is defended by two works and a platform battery, mounting in all twenty-three guns.  Marblehead, Mass., is defended by two works, mounting fifteen guns.  Salem, Mass., is defended by three works, mounting twenty guns, a portion of which contribute to the defense of Beverly Harbor.  Plymouth, Mass., is defended by two works, mounting twelve guns.  Provincetown Harbor, Mass., is defended by two inclosed batteries, mounting nine guns.  San Francisco, Cal. – Besides the permanent defenses in progress in this harbor, the following temporary works have been constructed during the past year: At Point San Jose, two batteries, mounting twelve guns; at Point Stewart, Angel Island, a battery mounting four guns; at Point Knox, Angel Island, a battery of ten guns, and at Point Blunt, Angel Island, a battery to mount seven guns.  Many of these defenses are inclosed works.  Roads have been cut, wharves built, quarters constructed, and the necessary magazines, bomb-proofs, and traverses provided to contribute to the defense and the accommodation of the gunners.

All of which is respectfully submitted,

RICHARD DELAFIELD, Brigadier- General and Chief Engineer

During the last two years many of the officers of the Corps of Engineers have been commissioned in the volunteer service as general officers and colonels in command of troops, as well as on general staff duty in the volunteer forces.  A number of others are detached from the Engineer Department for service in their special sphere with the armies in the field, both with engineer troops and on engineer staff duty.  By the act of March 3, 1863, the Corps of Engineers and the Corps of Topographical Engineers were united in a single organization as The Corps of Engineers, and the duties of the two, heretofore divided, are now discharged by the new corps, which, in accordance with the general military systems of other nations, administers the whole engineer service of the Army.  Of the officers of engineers serving with volunteers commissions there are now six major-generals, nine brigadier-generals, seven colonels, four lieutenant-colonels, and one major.  Sixteen of these are in command of troops, five are on general staff duty, and four are on engineer staff duty.

The whole number of engineer officers now serving in the field is fifty-two – twenty with troops and thirty-two on staff duty.

During the year two veteran officers have been removed from the corps by retirement consequent upon long and faithful service, two by promotion to be brigadier-generals of the Regular Army, four have fallen in battle, and one has lost his life directly in the act of rendering important professional service.

The loss of so large a number of the officers of the corps and the heavy demands of the active operations of the war upon its members have left but a small proportion available for the construction of the sea-board and frontier defenses, the requirements of the Military Academy, the lake surveys, and other ordinary duties.

At the same time the interests of the country require that the system of defenses should be pressed forward with all practical rapidity, and Congress appropriated unusually large sums of money for the purpose of expediting the works.  Labors upon them have been therefore pressed to the greatest extent that the difficulty of procuring workmen and materials and the capacity of the heavily-taxed officers in charge would allow, and corresponding progress has been effected, so that a number of important positions are now in condition to make a formidable defense, and at all where it was possible to labor very material progress has been effected.

Below will be given a statement of the condition of each fortification now under construction or repair, with an account of the progress made during the past year and the operations contemplated for the present and next year. These statements are for the most part in the words of the officers in charge of the works.

The above statement exhibits the condition of operations on the various permanent fortifications now in course of construction, modification, or repair.  During the last year, however, much solicitude has been entertained respecting a number of our towns and harbors to which the system of permanent fortifications has not thus far been extended.  In order to be ready to meet emergencies, projects for temporary defenses were prepared for a number of these points, and the construction of the works has been put in hand in measure as circumstances would allow.  In this way provision has been made for temporary batteries of from five to fifteen guns each at each of the following places, viz: Eastport, Machias, Castine, Belfast, Rockland, Newburyport, Gloucester, Salem, Marblehead, Plymouth, Provincetown, west entrance to Narragansett Bay, New Haven, Delaware River, opposite Fort Delaware, mouth of Columbia River, Oreg.  At each of these work is in rapid progress; the guns have been supplied, and the completion of all the batteries will be effected in a short time.

Very respectfully, your obedient servant,

I. C. WOODRUFF, Major of Engineers, in Charge.

[OR Series 3 Vol. 3 pages 962 - 963]