The first ammunition-boxes unloaded have their contents distributed, by the non-commissioned officer in charge, to the proper cannoneers of each gun detachment; and as soon as the contents of half the boxes have been fired three of the second ammunition-mules are sent to the front and their boxes removed; then, reloaded with empty boxes, they are sent to their position under cover. =To Supply the First Line from the Second Line.=--The first sergeant tells off six ammunition-mules to be in readiness to move to the front, under a non-commissioned officer, when required. As soon as the battery opens fire these mules are sent forward to the first line and remain there under cover. As soon as the first six ammunition-mules laden with empty boxes are assembled under cover they are sent back, under a non-commissioned officer, to the second line. CARE AND PRESERVATION OF HARNESS. All harness should be periodically taken to pieces and thoroughly examined. It should be oiled with neat's-foot oil two or three times a year, and kept soft and pliable. Good castile soap and water should be used for washing harness, and the dressing furnished by the Ordnance Department. This dressing is applied with a woollen cloth, left on until the next day, and then thoroughly wiped off with a woollen cloth. It is made as follows (ingredients for two gallons): 1 gal. neat's-foot oil, 2 lbs. bayberry tallow, 2 lbs. beeswax, 2 lbs. beef tallow. Place in a pan over a moderate fire and let the above ingredients remain one hour, until thoroughly dissolved; then add 2 quarts of castor oil and stir well until the mass comes to a boil, so that the ingredients may become thoroughly mixed; after which add 1 oz. lamp-black and stir well for ten minutes; then strain the liquid while hot through a cotton cloth to remove sediment of beeswax, tallow, and lamp-black, and put aside to cool. Colgate's black harness-soap and Frank Miller's harness-soap, No. 2½, are excellent for cleaning harness and keeping it soft. =Blacking for Harness and Bridle Leather.=--A decoction of iron-rust and vinegar, applied to the grain side of the leather after it has been stained. In staining, apply with a hair brush, a solution of logwood, sal-soda, and soft water. Iron parts when rusted should be cleaned with kerosene, wiped dry, and then have applied a light coating of asphaltum paint; allow it to dry and then apply a second coat. In the field there will not usually be much time or many materials for cleaning harness. Rust should be cleaned off ironwork with sand and then it should be oiled. Leather work should be kept soft and pliable. First remove the mud and dried sweat with as little water as possible and then work in a little oil or soft soap. INSTRUCTIONS FOR DRIVERS, ETC. The carriage-mule is always the leader when packing, or on the near side in draught. This mule should therefore be the most tractable and intelligent.