The armament is mainly made up of 24 and 32 pounders on sea-coast carriages, with a limited proportion of pounder siege guns, rifled Parrott guns, and.
The larger of the works are flanked, but the greater number are not, the sites and dimensions not permitting. Magazines are provided for one hundred rounds of ammunition, and many of the works have a considerable extent of bomb-proof shelter, as Forts Lyon, Worth, and Ward, in the bomb-proofs of which probably one-third of the garrison might comfortably sleep and nearly all take temporary shelter. In nearly all the works there are either bomb-proofs like the above, or log barracks, or blockhouses of some kind.
It would be impossible to go into any details about these constructions. I am in hopes ultimately to be able to deposit in the Engineer Office drawings of each work with sufficient detail for most purposes. The accompanying sheets, Nos. It should be observed that most of the works south of the Potomac, having been thrown up almost in the face of the enemy, have very light profiles, the object having been to get cover and a defensive work as speedily as possible.
The counterscarps of all the works, with few exceptions, are surrounded by abatis. It is impossible, at present, to indicate the exact extent of forest cut down.
The drawings herewith represent the forest as it existed before the works were commenced. This fallen timber most of which still lies on the ground. The sites of Forts Totten, Slocum, Bunker Hill, Meigs, Stanton, and others were entirely wooded, which, in conjunction with the broken character of the ground, has made the selection of sites frequently very embarrassing and the labor of preparing them very great. The only case in which forts are connected by earthworks is that of Forts Woodbury and De Kalb, between which an infantry parapet is thrown up,.
The construction here was suggested by the fact that this was on one of the most practicable and probable routes of approach for the enemy. We have been obliged to neglect much and even to throw out of consideration important matters. We have been too much hurried to devise a perfect system, and even now are unable to say precisely what and how many additional points should be occupied and what auxiliary arrangements should be made.
The necessity of protecting the Chain Bridge compelled us to throw the left of our northern line several miles in advance of its natural position, as indicated by the topography to the sites of Forts Ripley, Alexander, and Franklin. Between these and Forts Gaines or Pennsylvania one or two intervening works are necessary. Fort Massachusetts is entirely too small for its important position.
Auxiliary works are necessary in connection with it. Small tetes-de-pont are required around the heads of Benning's and the Navy-Yard Bridges. Between Forts Mahan and Meigs one or more intervening works and between Forts Du Pont and Davis another work of some magnitude are required, the ground along this line not being yet sufficiently known.
A glance at the map will show it to be almost a continuous forest. Considerable work is also required in the way of roads, the amount of which I cannot state with any precision. Several miles of roads have actually been made.
First Bull Run Union order of battle
The aggregate perimeter of all the works is about 15, yards, or nearly 9 miles, including the stockaded gorges, which, however, form a small proportion of the whole, requiring, computed according to the rule adopted for the lines of Torres Vedras, 22, men about for garrisons. The number of guns, most of which are actually mounted, is about four hundred and eighty, requiring about 7, men to furnish three reliefs of gunners.
The permanent garrisons need consist of only these gunners, and even in case of attack it will seldom be necessary to keep full garrisons in all the works. The total garrisons for all the works one hundred and fifty-two in number of the lines of Torres Vedras amounted to 34, men; and as the total perimeters are nearly proportional to the total garrisons, it appears that the lines about Washington involve a magnitude of work of about two-thirds of that in the three lines of Torres Vedras.
The works themselves, fewer in number, are generally much larger than those of Torres Vedras, and involve, I believe. As to number of guns, therefore, our armament approaches to equality with that of the famous lines mentioned; in weight of metal more than doubles it.
First Bull Run Union order of battle
The above applies to our works as now nearly completed, and has no reference to the additional works I have elsewhere mentioned as hereafter necessary. It is impossible to give any other statement of actual cost of the works than the total amount expended thus far.
The work has been done partly by troops and partly by hired laborers, the works north of the Potomac being mostly done by the latter. The importance of perfect security to the capital of the United States in the present state of affairs can scarcely be overestimated, and these works give a security which mere numbers cannot give, and at not a tithe the expense of defense by troops alone.
Thus following the defeat at First Manassas, gigantic efforts were directed toward designing and erecting a system of fortifications to protect Washington, D. After deciding that fortifications are necessary, the first thing to do, hopefully by an Army engineer officer, was to select the right location s. To effect this, all the ground around the fort, within range of the cannon, should offer no shelter to the enemy from its fire; th ditches should be flanked throughout; and the relief be so great as to preclude any attempt at scaling the work.
After the Army engineer officer selected the location of the fortification, he next needed to "throw up the work," "layout the work" or profile it. Some authors have described how to throw up a work:. The foregoing chapters contain all that is requisite to determine the plan and relief of field works under all circumstances of variety of ground. To follow a natural order, the next steps will be to describe the manner of laying the work out on the field, which is termed profiling; the distribution of the workmen to excavate the ditch, and form the parapet; and the precautions to be observed in the construction.
Poles Fig. At suitable distances, say from twenty to thirty yards apart, cords are stretched between two stout pickets, in a direction perpendicular to the line marked out by the pick; these cords should be exactly horizontal.
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A stout square picket is driven firmly into the ground, where the cord crosses above the pick-line, and a slip of pine, on which the height of the interior crest is marked, is nailed to the picket. The thickness of the parapet is measured on the cord, and a picket driven into the ground to mark the point. The base of the interior slope and tread of the banquette, are set off in a similar manner; and a slip of deal is nailed to each of the pickets.
The height of the interior crest, and the tread of the banquette, are easily ascertained, from the position of the cord, and the interior crest; these points having been marked on their respective slips, the outline of the parapet is shown by connecting them by other slips, which are nailed to the uprights; the banquette slope, and exterior slope, will be determined by a similar process.
From the profile thus formed perpendicular to the interior crests, the oblique profiles at the angles can readily be set up, by a process which will suggest itself without explanation. Having completed the profiling, the foot of the banquette, and that of the exterior slope, are marked out with the pick, and also the crests of the scarp and counterscarp.
All the arrangements preparatory to commencing the excavation are now complete.
Whatever the form is to be given to a work, it is traced upon the ground by laying off its angles according to the number of their degrees, and its sides are designated by little furrows dug with the mattock or spade along cords stretched in the proper direction. To profile a work is to figure upon the ground its elevation by means of poles and laths nailed together; Fig. The officer who directs the work ought to take with him four or five soldiers who carry mattocks, pickets, twenty poles ten or twelve feet long, twenty laths, some camp colors, and a cord 65 feet in length.
There ought to be a carpenter, who carries hammer, nails, and a saw. They may have any extent, from a simple redan, or a battery, to a line or several lines of works, some of considerable magnitude, extending over a position of ten or twenty miles. Thus, to the magistral line of each face and flank, trace on the ground perpendicularly at intervals, and on these measure, horizontally, the bases of the slopes composing the profile to be employed.
At the points thus set out fix poles or laths perpendicularly in the ground, and saw off their tops at the height which the parapet is to have at that particular part; nail laths to the tops of these poles from one to the other across the direction of the intended parapet; and thus there will be obtained an outline of the slopes, or a profile of the parapet. For the profile at an angle, lay a rope on the ground bisecting that angle, and produce it outwards; drive pickets along this rope at the points where it is intersected by the prolongations of lines joining the bases of the profiles already set up perpendicularly to the adjoining faces, these pickets mark the bases of the profiles at the salient; the laths may then be set up as before.
Some soldiers, who observed this construction and often actually worked on the fortifications themselves, penned descriptions:. The fort or earthwork was a very large one with a ditch or moat all round it. This was filled with water. The outside of the forts were sodded.
In building these works the engineers first built a light frame of wood the size and shape that it wanted, and when it is fixed to suit them with the necessary angles, etc. When it has been graded over nicely, it is covered over with sods. The ditch soon fills with water from the many rain storms, and after the Cheaveaux de Frisse that we employed were large branches of trees pinned to the ground, with the brush outward.
The ends of the branches were then cut off and sharpened, and it would have bothered man or horse to get over it.
A Companion to the U.S. Civil War - A Companion to the U.S. Civil War - Wiley Online Library
Axes and shovels were furnished and we were soon hard at work. To most of us this was an unfamiliar effort but before our service ended it was one in which we were to become proficient. There was a lot of fallen timber that we gathered and placed lengthwise, then dug a trench behind, with the dirt thrown over the logs.
The trench was over two feet deep, wide. These works were quite strong and would protect the men against attack, for an ordinary projectile could not go through the embankment. Among other duties, the Corps of Engineers planned, designed and oversaw the construction and maintenance of fortifications while the Corps of Topographical Engineers was the Army's surveyors and cartographers, often surveying and mapping fortifications.
The two corps combined in because there weren't enough Army engineers for two to serve on the staff of all the commands within the Union Army. Following the merger, Army Engineers were responsible for surveying and mapping fortifications as well as planning, designing and overseeing their construction and maintenance. The Army Engineers planned, designed and erected numerous fortifications throughout the country during the Civil War but the Defense of Washington, D.