When camp is made for a single night, shallow trenches, 12 inches deep and 15 to 18 inches wide, which the men may straddle, will suffice. In more permanent camps, the trenches should be about 2 feet wide, 6 feet deep, and 15 feet long. They should be provided with seats and back rests made of poles, and should be screened by brush or old tent flys. 675. In cold weather the contents of sinks should be covered once daily with quicklime, ashes, or dry earth. When filled to within 2 feet of the top, sinks should be discontinued and filled in. Open pits are dangerous during the fly season. However, the danger may be greatly reduced by covering the excreta with earth or by a thorough daily burning of the entire area of the trench. Combustible sweepings or straw, saturated with oil, may be used for this purpose. In fly season, trenches may be closed with seats covered down to the ground with muslin and supplied with self-closing lids. Urinal troughs, made of muslin and coated with oil or paint, should discharge into the trenches. 676. In permanent camps special sanitary facilities for the disposal of excreta will ordinarily be provided. If necessary, urinal tubs may be placed in the company streets at night and removed at reveille. Their location should be plainly marked and thoroughly and frequently disinfected. 677. When troops bivouac for the night the necessity for extensive sanitary precautions is not great; however, shallow sink trenches should be dug to prevent general pollution of the vicinity. If the cooking be collective, shallow kitchen sinks should be dug. If the cooking be individual, the men should be required to build their fires on the leeward flank of the camp or bivouac. Before marching, all trenches should be filled in. _PROTECTION OF CAMP OR BIVOUAC._ _General Considerations._ 678. The outpost is a covering detachment detailed to secure the camp or bivouac against surprise and to prevent an attack upon it before the troops can prepare to resist. 679. The size and disposition of the outpost will depend upon many circumstances, such as the size of the whole command, the proximity of the enemy and the situation with respect to him, the nature of the terrain, etc. A suitable strength may vary from a very small fraction to one-third of the whole force. For a single company in bivouac a few sentinels and patrols will suffice; for a large command a more elaborate outpost system must be provided. It should be no stronger than is consistent with reasonable security. The most economical protection is furnished by keeping close contact with the enemy by means of outpost patrols, in conjunction with resisting detachments on the avenues of approach. The outpost should be composed of complete organizations.