This operation is independent of the condition of the atmosphere and only requires the care mentioned. DRYING BY EXPOSURE IN A DRY ATMOSPHERE. String the blocks to be dried on a wood, brass or copper rod or pipe, which must be free from dirt and oil, or place them on a shelf made of wire netting, separating the blocks from each other to expose all surfaces freely to the air; suspend the rod or shelf in some suitable place not in the vicinity of the galley or other fires, where the blocks will be freely exposed to the air, and be under cover. Expose the blocks only when the atmosphere is dry; at all other times keep them in an empty powder tank, in the immediate vicinity of the place selected for drying, kept closed to exclude moisture. Weigh the blocks every two days, noting the date and weight with a soft lead-pencil on them. Continue the drying until the blocks show no loss of weight for two consecutive weighings; then place them in the glass jars, with strips of blue litmus-paper between, and treat them according to the rules given for dry gun-cotton primers. This plan can only be carried out in dry climates. Avoid unnecessary handling of the blocks, as they are apt to flake and crumble. MISCELLANEOUS DATA. Dimensions of gun-cotton blocks length 2.9 inches. width 2.9 ” height { 2.0 ” for full sized blocks, { 0.5 ” for primer blocks. Diameter of detonator hole = ⁷/₁₆ inch. Pressure applied to blocks in the final press = 6800 lbs. per square inch. Average gravimetric density of compressed dry gun-cotton = 1.287. Average weight of one cubic inch of compressed dry gun-cotton = 325 grains, = 0.743 oz. Weight of water added to each pound of dry gun-cotton when issued to the service as wet gun-cotton (approximately 35%) = 0.35 lb. = 5.6 oz. APPENDIX. DUTIES OF THE INSPECTOR OF ORDNANCE.—LIST OF ARTICLES IN OUTFIT, WEIGHTS AND STOWAGE SPACE. DUTIES OF THE INSPECTOR OF ORDNANCE AT THE NAVY YARD IN CONNECTION WITH THE TORPEDO OUTFIT OF A SHIP. GUN-COTTON MAGAZINE. He will carefully inspect the gun-cotton magazine, satisfy himself that it is constructed in accordance with the Ordnance Instructions concerning shell-rooms, and the directions given on pages 40 and 41 Spar-Torpedo Instructions, that it is of sufficient size to stow the portion of the torpedo outfit defined in the “Table showing Weight, Space and Place of Stowage of Articles in Spar-Torpedo Outfit” and will prepare a plan of stowage. TORPEDO STOREROOM. He will carefully inspect the torpedo store-room, satisfy himself that it is in a proper position with regard to battery and boilers, that it is not exposed to undue changes of temperature, or to accidental admission of water, and that it is of sufficient capacity and conveniently arranged to stow the portion of the outfit defined in “Table showing Weight, Space and Place of Stowage of Articles in Spar-Torpedo Outfit.”