The Ordnance Department now limits the operations at arsenals to the construction of wrought-iron sea-coast carriages and such ordnance supplies as are needed for immediate use; preservation of the ordnance store left on hand at these close of the war; breaking up unserviceable ammunition, and completing unfinished buildings. Fireproof workshops have been completed at Watervliet, Frankford, and Alleghany Arsenals" there magazines, with a capacity for storing 15,000 barrels of gunpowder, have been built at Saint Louis Arsenal, and one of the same capacity at each of the arsenals at Washington City and Benicia. A board of officers is engaged in examining suitable sites for depositories of gunpowder provided for by an appropriation of the last session of Congress; and the erection of such magazines as will furnish secure and suitable storage for all our powder, ammunition, and niter will be commenced early next spring. The arsenals at the South which were seized by the rebels, having been retaken, are reoccupied, excepting the North Carolina Arsenal, which was destroyed; the Harper's Ferry Armory, the workshops of which were burned, and which has been used as an ordnance depot; the arsenal in Florida, which has been transferred temporarily to the Freedmen's Bureau, and the arsenal in Arkansas, which is occupied by troops of the line. The Chief of Ordnance is of opinion that it is advisable to rebuild the North Carolina Arsenal or to re- establish the armory at Harper's Ferry, and the sale of both is recommended. All the small-arms and some of the other supplies which were collected at Baton Rouge, San Antonio, Augusta, Charleston, and Mount Vernon Arsenals have been removed, and the only supplies which have been sent to them were such as were required for immediate issue to troops. The commission appointed under the act of April 19, 1864, to examine and report the value of property on Rock Island taken by the United States by authority of that act has entered upon its duties. As soon as good titles to the property shall have been acquired the construction of the armory and arsenal, as required by law, will be hastened as fast as the appropriations will admit. It is important that this establishment should be built up as rapidly as possible, and a considerable sum has been estimated for that purpose during the next fiscal year. It is believed that all of it is necessary and can be judiciously and advantageously expended. The operations at the National Armory at Springfield, Mass., during the past year have been confined to cleaning and repairing arms used during the war, and to making the requisite preparations for converting the Springfield muskets into breech- loaders. The power and endurance of the 8-inch and 12-inch cast- iron rifle cannon have been subjected to practical tests, and the experiments, will be continued. The ordnance returns for three consecutive years, including a period of active service and ordinary repairs, show an average duration of five years for cavalry carbines, of four years for cavalry pistols, sabers, and accounterments, of seven years for infantry muskets, and of six years for infantry accounterments. From January 1, 1861, to June 30, 1866, the Ordnance Department provided 7,892 cannon, 11,787 artillery carriages, 4,022,130 small-arms, 2,362,546 complete sets of accouterments for infantry and cavalry, 539,544 complete sets of cavalry horse equipments, 28,164 sets of horse artillery harness, 1,022,176,474 cartridges for small-arms, 1,220,555,435 percussion-caps, 2,862,177 rounds of fixed artillery ammunition, 14,507,682 cannon primers and fuses, 12,857,294 pounds of artillery