During the past fiscal year no operations have been carried on, except for the care and preservation of the work. No appropriation was made for the fiscal year ending June 30, 1877. Fort at Fort Point, entrance to San Francisco Harbor, California, in charge of Lieut. Col. C. S. Stewart, Corps of Engineers.-This is one of the principal works for the defense of the entrance to the harbor of San Francisco, through the Golden Gate, the approaches to this entrance and the inner waters of this passage. The breast-height walls for six heavy guns have been completed, and the concrete foundations for two heavy-gun platforms put in place. A drain has been constructed at south end of battery 6-7. In all, making 475 cubic yards of masonry. There have been embanked in parapets and traverses 8,365 cubic yards of earth, and there have been placed on the slopes 3,777 square yards of sodding. The doors have been finished and hung in seven traversemagazines. The usual miscellaneous repairs of buildings, bulkheads, fences, roads, &c., have been made. No appropriation was made for the fiscal year ending June 30, 1877. $60,000 Fort at Lime Point, San Francisco Harbor, California, in charge of Maj. George H. Mendell, Corps of Engineers.-This fort, with its detached earthen barbette works, at Point Cavallo, Lime Point Ridge, and Gravelly Beach, constitute the defenses of the entrance to the harbor of San Francisco, on the northern shore of the Golden Gate. No new battery was begun during the year, but operations were confined to placing hoods on the traverses at Point Cavallo battery, and to repairs at the Ridge and Gravelly Beach batteries, together with essential repairs to the roads and to the breakwater. The platform spaces between the timbers at Gravelly Beach were filled with concrete, consuming 98 yards. The platforms were painted and the terreplein graded. The parapet of one of the guns at the Ridge battery, where there is a heavy filling, having settled, 2,100 yards of material was added. No platforms were laid in this battery, but the timbers for five wooden platforms were prepared for laying. The hoods and adjacent portions of parapets and slopes in the Point Cavallo battery were sodded. Four thousand yards of earthwork and 2,535 square yards of sodding were laid on the hoods and parapets of the batteries. To complete these three batteries, there remain to build 7 breast-height walls in Point Cavallo battery and to lay 17 platforms. In the Ridge battery, 5 platforms remain to be laid. No appropriation was made for the fiscal year ending June 30, 1877. $80,000 Fort on Alcatraz Island, San Francisco Harbor, California, in charge of Maj. George H. Mendell, Corps of Engineers.-This work occupies a valuable position for the defense of the entrance to and the inner waters of the harbor of San Francisco, covering the whole of a rocky island, the shores of which rise abruptly from the water to a height sufficient to secure it from surprise. The fortifications have from their inception consisted chiefly of open barbette batteries for the heaviest guns. Two magazines and bomb-proofs have been built during the year. One has been covered and sodded and the other nearly covered. Three adjacent wings of the breast-height wall, necessary to sustain the hoods of the traverses, have been built. A part of the sewer from the defensive barrack was rebuilt, it having been broken in the excavation for oue of the magazines. Two drains in batteries 10 and 12 were also built or extended. The wharf was repaired with new piles. The principal items of work done in the past year are as follows, namely: Excavation, 36,366 cubic yards; sodding, 876 square yards; plastering, 1,331 square yards; brick masonry, 9 yards, and concrete, 1,150 yards. The operations of the present fiscal year will be mainly in excavation by prisoners under charge of a kind overseer. No appropriation was made for the fiscal year ending June 30, 1877. $50,000 Batteries at Point San José, San Francisco Harbor, California, in charge of Lieut. Col. C. S. Stewart, Corps of Engineers.-These temporary batteries are in an unserviceable condition; the timber platforms and revetments and timbers of the magazines are rotten and falling to pieces. No work was done during the past fiscal year and none is contemplated during the present year. Batteries on Angel Island, San Francisco Harbor, California, in charge of Lieut. Col. C. S. Stewart, Corps of Engineers.-These three temporary earthworks, constructed during the late war, are essentially unserviceable; the platforms are decayed, and most of the carriages have been con demned. It is not intended to commence the construction of batteries of a permanent character projected to replace them until more advanced points of the exterior line of defense are fortified. Fort at San Diego, Cal., in charge of Lieut. Col. C. S. Stewart, Corps of Engineers.—This work is situated on Ballast Point, near the mouth of the bay and harbor of San Diego, and commands the channel of entrance thereto. No work was done at this work during the past fiscal year, there hav ing been no appropriation made therefor. A watchman was employed throughout the year to care for the work and public property pertaining thereto. The work and property are in fair condition. No appropriation was made for the fiscal year ending June 30, 1877. $50,000 Defenses of the mouth of the Columbia River, Oregon, in charge of Maj. N. Michler, Corps of Engineers, until December 28, 1875; since that date in charge of Maj. John M. Wilson, Corps of Engineers.-These defenses consist of Fort Stevens, Point Adams, Oregon, on the south side, and Fort Canby, Cape Hancock, Washington Territory, on the north side of the entrance to the river. These works are earthen barbette batteries, and constitute the only defenses of the mouth of the Columbia River. Fort Canby. The three batteries require extensive repairs; two of the service-magazines are unfit for use; the wooden revetments and platforms are rapidly decaying; the roads leading to the batteries should be repaired. During the past fiscal year the magazine of the west battery has been rebuilt, two 10-inch-gun platforms in the east battery have been rebuilt, and new revetments placed in front of them. Fort Stevens.-This work is in a very dilapidated condition; the wooden revetments have badly decayed; the breast-height walls have given way and the traverses are in ruins; the platforms and magazines need repairs, and the drainage of the ditch requires attention. During the past fiscal year a new platform has been constructed for the 15-inch gun and the revetment in front renewed. The revetment has also been renewed in front of one 10-inch and three 8-inch guns, and the earthwork adjacent graded and sodded. Surveys have been made of Saud Island, Point Adams, Clatsop Spit, and the swash channel, and charts prepared. No appropriation was made for the fiscal year ending June 30, 1877. BOARDS OF ENGINEERS. $20,000 The Board of Engineers for Fortifications, stationed in New York City, consisting of Col. J. G. Barnard, Col. Z. B. Tower, and Lieut. Col. H. G. Wright, and, for the time being, the officer in charge of the defenses under consideration, has, during the past fiscal year, been chiefly engaged upon plans for casemated work with iron shields, to occupy the present site of Fort Lafayette, New York Harbor; for modification of proposed exterior batteries at Fort Taylor, Florida; for revision of proposed batteries at Points Blunt and Knox, and Camp Reynolds, and for occupation of Point San José, San Francisco Harbor, California; for modification of proposed batteries for defense of Dutch Island, Rhode Island; for battery for defense of Tybee Roads, at the mouth of the Savannah River, Georgia; and for barracks at Fort Monroe, Virginia. Reports have also been made upon the following subjects: Of repairs of injuries to the cover-face of Fort Taylor, Florida, and construction necessary to prevent its further damage by storms; of proposed defenses of Galveston, Tex.; of allowing the use of the Government buildings on Cockspur Island, or of the site for proposed defenses on Tybee Island, Georgia, for the purpose of a naval station; in reference to the adaptation of the Gatling-gun carriage to flank embrasures; as to the disposition of a casemate shield on store at Pittsburgh, Pa.; and of carriage recommended for the 10-inch guns now being converted by the Ordnance Department into 8-inch rifles. Reports and drawings have been submitted showing proposed arrangement of torpedo lines for the harbors of Portland, Me., Portsmouth, N. H., Boston, Mass., New London, Conn., Charleston, S. C., of Patapsco River, Md., Newport Harbor, R. I., Dutch Island, R. I., Potomac River, Md., Hampton Roads, Va., Savannah River, Ga., Pensacola, Fla., Key West, Fla., and Mobile Bay, Ala. During the month of March, 1876, Generals Tower and Wright inspected the defenses at Key West and Tortugas, Fla., "notes" of which inspection were submitted May 3. In addition to the foregoing, the board has had under consideration the defense of the Hussey's Sound entrance to Portland Harbor, Me., and plans of batteries to command this entrance and the inner anchorage are in progress. TORPEDO DEFENSE. In this connection, Maj. H. L. Abbot, in command of the engineer battalion and the post of Willet's Point, is ex officio a member of the board, and the executive officer by whom the experiments have mainly been made and the details of our system worked out. In the last annual report so complete a general summary of the scope of the trials now making for the development of the torpedo as an auxiliary in harbor defense was given, that it is only needful here to refer to that paper, and to recapitulate the progress made during the past year. Experiments with the iron target have been continued with results which may be briefly summed up as follows: Five shots were fired, viz, 50 pounds of dynamite 30 feet below the bottom of target and 5 feet horizontally from one of its angles; 75 pounds 30 feet below the bottom and 8 feet horizontally from an angle; 100 pounds in a position similar to the last; 100 pounds 30 feet below the bottom and vertically under an edge; and, lastly, 100 pounds 20 feet below the bottom and vertically under another edge. The last shot sunk the target, and when it was raised and examined, the whole structure was found to be so weakened that extensive repairs have been necessary. The plug indications have been of a character to give much valuable data concerning the several shots, as has been already reported in detail. The target has been put in perfect order and the trials will soon be resumed. The experiments with the torpedo-crate have been brought to a successful termination, as follows: 30 pounds of dynamite were exploded without doing any injury except deeply corrugating the buoys. Fifty pounds collapsed the latter, as was expected, letting crate down; but it was raised uninjured. It was then placed cn the bottom, in 19 feet of water, and 40 pounds exploded without injury. It was again placed on the bottom, in 13 feet of water, and 100 pounds were exploded, effectually breaking up the apparatus. In all these shots the plugs were safely recovered, and their indications, in connection with those of former shots, supply all the data which the experiments were designed to secure. A series of severe trials of torpedo-cases to determine their strength to resist the blows of large steamers moving at high rate of speed have been carried out with very satisfactory results. All parts of the system perfectly fulfilled their functions. The exact time of each blow was automatically recorded, and the guard was electrically notified not only of each contact, but also whether it caused any injury. Experiments directed to improving the manufacture of the cases have proved successful, and all bolts and nuts are now avoided in their construction. A perfect disconnecter has been devised by Major Abbot, who has also improved his circuit-closer, so that without extra expense it serves now equally well as a circuit-breaker. Many severe tests have shown it to combine certainty of action with great simplicity and trifling cost. A ground torpedo, rendered unserviceable by a crack, was planted in the autumn, charged with 200 pounds of dynamite. After remaining submerged for six months, with the charge thoroughly wet, and most of the time frozen, it was fired with tremendous effect on the first trial, the temperature of the water being still below the freezing-point of nitroglycerine. Several new forms of battery have been subjected to careful measurements, with valuable results, and much other laboratory investigation has been successfully carried out. Incidentally, the general theory of simultaneous ignition of mines has received a mathematical and experimental study, which has developed the principles which should govern the engineer in arranging the connections and determining the minimum battery-power. The value of this investigation for many works of internal improvement is apparent. Good progress in preparing the Torpedo Manual has been made by Major Abbot, and it is expected that this important work will be completed during the coming season. In conclusion, the board would repeat its opinion, fully stated last year, that the system of applying torpedoes to harbor defense has now reached so high a degree of perfection, that it is urgently necessary to provide a large number of engineer soldiers instructed in the details of its practical application to our harbors. Not less than 520 men should be kept ready for instant service, a number which is considerably less than the legal organization of the battalion, although larger than the force now authorized to be kept in service. For continuing the purchase of such parts of the torpedo-material as cannot suddenly be procured in case of war, an appropriation of $150,000 is recommended. The Board of Engineers for the Pacific Coast during the past fiscal year has consisted of Lieut. Col. B. S. Alexander, Lieut. Col. C. S. Stewart, and Maj. George H. Mendell. Lieut. Col. R. S. Williamson was assigned as a member of this board by special orders No. 6, dated Headquarters Corps of Engineers, Washington, D. C., January 18, 1876, and has acted in that capacity ever since. During the year the board has acted and reported upon consideration of project, report and estimate for the improvement of San Diego Harbor; consideration of encroachments of Columbia River and the sea on the shore of Point Adams, threatening the site of Fort Stevens, Oregon; report concerning sea-wall at the city of San Francisco, Cal.; consideration of and report on the filling up of the channels of the Columbia River in the vicinity of Point Adams, Oregon; studies on the subject of a harbor of refuge on the Pacific coast, and report on the value to the United States of certain lands adjacent to San Diego. BATTALION OF ENGINEERS AND ENGINEER DEPOTS. Battalion of engineers, commanded by Maj. Henry L. Abbot, Corps of Engineers, headquarters Willet's Point, eastern entrance to New York Harbor. The strength of the engineer battalion on June 30, 1876, was sixteen comissioned officers and two hundred and forty-eight enlisted men. The companies were stationed and commanded as follows: At Willet's Point, Company A, Capt. James Mercur; Company B, First Lieut. J. B. Quinn; Company C, Capt. W. R. Livermore; Company D, (a skeleton organization,) First Lieut. Edgar W. Bass, battalion adjutant. At West Point, Company E, Capt. O. H. Ernst, also instructor in practical engineering at the Military Academy and ex officio member of the academic board. Detachments have served as follows: Department of the Missouri, three non-commissioned officers and four privates; Department of Dako ta, two non-commissioned officers and five privates; under Lieutenant Wheeler, on the surveys of the Territories, two privates; at the Centennial Exposition at Philadelphia, one commissioned officer, three noncommissioned officers, and seven privates. Recruiting has remained discontinued, the only exception being reenlistments, and enlistments at West Point for Company E to supply vacancies in its numbers. During the year thirteen men were enlisted, thirty-five were re-enlisted, thirteen deserted, and three were apprehended from desertion. The duties of the battalion have consisted in guarding the depot, and remodeling public buildings at Willet's Point, and receiving and issuing the property as ordered; in instructing the cadets at the Military Academy in field engineering, including military signaling; in experimentally developing the details of the torpedo service, and performing the labor required to carry out the approved project of trials therefor; in drilling in field fortification, military bridge-making, field reconnais sance, photography, target practice, and infantry tactics. The detachments in the Indian country have been employed in military map-making, under the direction of the officers of the corps serving with the troops in those departments, and their efficiency and usefuluess have |