points early in August. The others were taken up as speedily as the clearing of the woods and the means at our disposal would admit, and the gaps in the line afterwards partially filled up by construction of Fort Gaines, Forts De Russy, Slemmer, and Thayer. The works mentioned are at this date essentially completed and armed, though there is still considerable to do in auxiliary arrangements. Our first ideas as to defensive works beyond the Anacostia contemplated only the fortification of the debouclies from the bridges (Navy-Yard Bridge and Benning's Bridge), and the occupation of the heights overlooking the Navy-Yard Bridge. With that object Fort Stanton was commenced early in September. A further examination of the remarkable ridge between the Anacostia and Oxen Run showed clearly that, to protect the navy-yard and arsenal from bombardment, it was necessary to occupy an extent of 6 miles from Berry's place (Fort Greble) to the intersection of the road from Benning's Bridge (Fort Meigs). Forts Greble and Carroll were commenced in the latter part of September, and Fort Mahan, near Benning's Bridge, about the same time. Forts Greble and Stanton are completed and armed; Forts Mahan and Carroll very nearly so. To fill up intervals or to sweep ravines not seen by the principal works, Forts Meigs, Dupont, Davis, Baker, Good Hope, Battery Ricketts, and Fort Snyder have been commenced, and it is hoped may be so far advanced before the winter sets in as to get them into a defensible condition. The occupation of the Virginia shore at the Chain Bridge was essential to the operations of our army in Virginia. It was only delayed until our force was sufficient to authorize it. General Smith's division crossed the bridge September, and Forts Ethan Allen and Marcy were immediately commenced and speedily finished. A few weeks later (September 28) the positions of Upton's and Munson's Hills and Taylor's Tavern were occupied and Fort Ramsay commenced on Upton's Hill. The enemy's works on Munson's and the adjacent hill were strengthened and a lunette built near Taylor's Tavern. Comprised in the foregoing categories there are twenty-three field forts south of the Potomac, fourteen field forts and three batteries between the Potomac and Anacostia, and eleven field forts beyond the Anacostia, making forty-eight field forts in all. These vary in size from Forts Runyon, Lyon, and Marcy, of which the perimeters are 1,500, 937, and 736 yards, down to Forts Bennett, Haggerty, and Saratoga, &c., with perimeters of 146, 128, and 154 yards. The greater portion of them are inclosed works of earth, though many-as Forts Craig, Tillinghast, Scott, &c., south of the Potomac, and Forts Saratoga, Gaines, &c., on the north-are lunettes with stockaded gorges. The armament is mainly made up of 24 and 32 pounders on sea-coast carriages, with a limited proportion of 24-pounder siege guns, rifled Parrott guns, and guns ou field carriages of lighter caliber. 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 block-houses 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. 1 and 2, will exhibit the general location and bearings of the works.* The tabular statement herewith will show the perimeters, number of guns, amount of garrison, &c.t 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.) The woods in advance of Forts Worth, Ward, and Blenker have been felled; all surrounding and between the next work on the right and Fort Richardson; all the wood on the ridge on which is Fort Scott-a square mile probably-in advance of and surrounding Forts Craig, Tillinghast, and Woodbury, besides large areas north of the Potomac, &c. This fallen timber (most of which still lies on the ground) rendered an enemy's approach to the lines difficult. 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, with emplacements for field guns. 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. Infantry trenches have, however, been constructed around or in advance of other works, either to cover the construction (as at Fort Lyon), or to see ground not seen by the work (as at Forts Totten, Lincoln, Mahan, &c.). The works I have now described do not constitute a complete defensive system. 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. It is safe to say that at least two additional works are required to connect Fort Ethan Allen with Fort De Kalb. 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. Between Forts Pennsylvania and De Russy at least one additional work is necessary. Fort Massachusetts is entirely too small for its important position. Auxiliary works are necessary in connection with it. Small têtes 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 To appear in Atlas. No tabular statement found as an inclosure to this report, but sce Barnard and Barry to Williams, October 24, pp. 626-623. + Omitted. glance at the map will show it to be almost a continuous forest. It is not deemed necessary to connect the works by a continuous line of parapet, but the intervening woods should be abatised and open ground traversed by a line of artificial abatis, and infantry parapets, half-sunk batteries, &c., placed so as to protect these obstructions and to see all the irregularities of the ground not now seen from the works. 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. The works themselves would be very much strengthened by caponieres in the ditches, additional internal block-houses, or defensive barracks, &c. The aggregate perimeter of all the works is about 15,500 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, 22,674 men (about) for garrisons. The number of guns, most of which are actually mounted, is about four hundred and eighty, requiring about 7,200 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 34,125 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, when the amount of bomb-proof shelter in ours is considered, more labor per yard of perimeter; but the latter lines involved a greater amount of auxiliary work, such as the scraping of mountain slopes, palisading, abatis, roads, &c., than we have had occasion to make. The lines of Torres Vedras were armed with five hundred and thirtyfour pieces of ordnance (12, 9, or 6 pounders, with a few field howitzers); ours with four hundred and eighty pieces, of which the greater number are 32-pounders on barbette carriages, the rest being 24-pounders on the same carriages, 24-pounder siege guns, 10, 20, and 30 pounder rifled guns (Parrott), with a few field pieces and howitzers. 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. 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 large amount of carpentry in magazine frames and doors and blindages, barrier gates, stockades, block-houses, defensive barracks, &c., has kept a large gang of carpenters all the time at work, and caused a large expenditure for lumber. The entire amount made available by the Department for these works has been $344,053.46, and this will all have been expended (or more) by the end of the present month. This would give an average of a little over $7,000 for each of the forty-eight works; but of course the real cost of them has been very unequal. The importance of perfect security to the capital of the United States in the present state of affairs cau 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. It is impossible to make anything like a reliable estimate of what additional amount of funds will be required. In a letter to the Generalin-Chief commanding Army of the Potomac, of December 6, I urged an immediate appropriation of $150,000, and this appropriation has been asked for of Congress by the Secretary of War. Should the auxiliary works which I have suggested be undertaken and the scarps be revetted, I believe a larger sum than this may be judiciously expended. I therefore recommend that an additional $100,000, or $250,000 in all, be provided for the continuation and completion of the defenses of Washington. These works acquire new importance if the probability of a foreign war is taken into consideration. In view of this new importance, of the semi-permanent or possibly permanent necessity for such works, it is proper to suggest that early in the spring the scarps be protected by a timber or thin brick revetment, and the exterior and other slopes, where not already done, be sodded, and that wooden caponieres, or counterscarp galleries, be arranged to flank all unflanked ditches-at least of important works. The strengthening of the profiles where necessary has already been mentioned as important. It remains with me to express my sense of the zeal and efficiency with which the officers of engineers serving with me since April have discharged their duties. To their energy and skill I am mainly indebted for the successful accomplishment of this really great work, and I feel that I have a right to say that for the safety of the capital in the hour of its greatest danger; for saving the cause of established government and the Constitution from the most serious blow the rebels could have inflicted, the country owes much to the labors of the engineers. From their great experience and constant association with me since April the services of Colonels Woodbury and Alexander have been particularly important in the laborious reconnaissances and in directing the execution of extensive lines of works. General Wright laid out and superintended the construction of Fort Ellsworth, and General Newton, who since the 1st of September until recently had charge of the works below Four Mile Run, laid out and directed the construction of Fort Lyon. Captains Blunt and Prime, Lieutenants Comstock, Houston, McAlester, Robert, Paine, Cross, Babcock, and Dutton have served with efficiency during the whole or part of these constructions, and the lamented Snyder lost his life from over-zealousness in discharge of his duties while in impaired health from his services at Charleston Harbor and Fort Sumter. Since the relief of Captain Prime, Lieut. H. L. Abbot, of the Topographical Engineers, has taken his place, proved himself a most energetic and valuable assistant, having completed Fort Scott and built Forts Richardson and Barnard. In carrying out so many works at the same time, and for organizing and managing the large bodies of hired laborers employed, it has been found necessary to call in the aid of civil engineers, not only because the engineer officers were too few to keep proper supervision, but because a large portion of those under my orders have been called off to other duties, such as the organization of bridge trains, the instruction of engineer troops, &c. Civil Engineers Gunnel, Frost, Faber, Childs, and Stone have rendered valuable services; also Mr. (now major of the Fifteenth New York Volunteer Regiment) Magruder. I should also express my warmest acknowledgment to Mr. James Eveleth, of your office, who, as disbursing agent and pay. master of the large bodies of hired laborers, has performed an amount of duty I should hardly have expected from one individual. I could wish that the law under which he serves the Engineer Department, might be so modified in his case as to enable him to receive some ade. quate compensation for the extra duties he has voluntarily assumed. I should have mentioned, in connection with my statement of the amount actually expended, that the Treasury Department has advanced over $20,000 on account of the defenses of Washington, which should be refunded. I feel it my duty in this place to urge that Congress should take immediate measures to assess the land and other damages arising from these works and from the occupation of troops. In most cases the owners are ill able to bear temporarily the losses to which they have been subjected. In conclusion, I would add that to the great importance attached to these works by the commanding general (now Commander-in-Chief), to his valuable suggestions and prompt and cordial co-operation, the present state of efficiency of the defenses of Washington is in no small degree due. I am, very respectfully, your obedient servant, J. G. BARNARD, Maj. of Eng., Brig. Gen., and Chief Eng. Army of Potomac. GENERAL ORDERS, No.. 33. } HDQRS. CORPS OF OBSERVATION, Poolesville, December 10, 1861. In compliance with Special Orders, No. 322, of December 6, 1861, headquarters of the Army, received this day, the undersigned assumes military supervision of the Chesapeake and Ohio Canal. All officers commanding lines of pickets between Great Falls and the Monocacy River are commanded, and all officers commanding pickets and lines of pickets along other portions of the canal are requested, to give all aid and assistance in their power, consistent with the good of the service, to the Canal Company authorities in the preservation and improvement of the canal. CHAS. P. STONE, Brigadier-General, Commanding. GENERAL ORDERS, No. 16. HDQRS. DEPT. WESTERN VIRGINIA, I. The headquarters of the Department of Western Virginia will until further orders be Wheeling, Va. By command of Brigadier-General Rosecrans: GEO. L. HARTSUFF, HEADQUARTERS, Baltimore, December 12, 1861. Hon. S. P. CHASE, Secretary of the Treasury: SIR: In a letter to you of the 5th instant I mentioned, in connection with a recommendation of two persons in Accomac and Northampton |