=To Measure a Distance with the Odometer.=--Tie the case by its straps to a spoke close to the hub of a hind wheel of any vehicle attached to the command. Upon starting read the odometer and record the reading. At the end of the course again record the odometer-reading. The difference between the two readings multiplied by the circumference of the wheel will give the distance passed over. And in general, the difference between any two readings, multiplied by the circumference of the wheel which bears it will give the development of the path traversed by the wheel between the points at which the readings were taken. CAMPS AND CAMPING SELECTION OF CAMPS. Avoid camping or bivouacking in graveyards. Get as far to windward of them as possible. Avoid ground that has been encamped on before, and if obliged to camp near it go to windward of old site. Avoid all rivers with marshy banks, and marshes of every description. If obliged to camp with a small force for a day or two near a marsh, if possible place yourself so as to have a hill or even some rising ground or woods between you and it. In camping near a stream cross it before making camp if possible and select a rise of ground near by. Low ground is unhealthy. All brushwood should be avoided, as also forests lately cut down. A grass country with a sandy or gravelly subsoil is best; land with a clayey subsoil is damp. There should be good natural drainage, and the location should be near fuel, water, and the road. LAYING OUT THE CAMP. Having fixed on the general plan of a camp, lay out the lines the tents are to occupy, and drive pegs to mark the position of the tent-poles or the centre of each tent. For wall-tents the distance between tent-poles of adjacent tents should be at least 20 feet. CAMPING. On arriving in camp park the battery with sufficient intervals to allow each horse at least a yard and a half on the picket-line, and have the wagons take positions most favorable for unloading. The sections of picket-rope are usually stretched along the spare wheels of the caissons by cannoneers under supervision of the gunners. Then the cannoneers, while drivers are unharnessing, etc., are told off into detachments, each under a non-com. officer when necessary, for unloading wagons, pitching tents, obtaining wood and water, and preparing latrines. The drivers as soon as dismounted are directed to unhitch, and if the animals are sufficiently cool they should be watered and fed.