=To Make Field-ovens.=--Take any barrel (the more iron hoops on it the better), the head being out; lay it on its side, having scraped away the ground a little in the centre to make a bed for it; or if there is a bank near excavate a place for it, taking care that the front end of the barrel is at least 6 inches back from the foot of the bank. Cover it with a coating of about 6 or 8 inches of wet earth or thick mud, except at the open end, which is to be the mouth of the oven. Pile up some sand or earth to the thickness of about 6 inches over the mud, arranging for an opening 3 inches in diameter being left as a flue (to increase the draught) to lead from the upper side of the barrel, at the far end, through the mud and earth. This flue is only left open when the fire for heating is burning; when bread is put in, it should be covered over. Form an even surface of well-kneaded mud at the bottom within the barrel to form a flooring to place the bread on. Light a fire within the barrel and keep it up until the staves are burnt, and the oven is then completed. When required for use, heat it as if it were an ordinary oven; draw out ashes; put in bread, and close the mouth with pieces of board, tin, or iron. The Subsistence Department issues an excellent pamphlet on army cooking. DRINKING-WATER. The water should be well tested, and persons living near by questioned about it. [Illustration: FIG. 80.] =Filters.=--Two barrels (Fig. 80), one inside the other, having a space of from 4 to 6 inches clear all round between them filled with layers of gravel, sand, and charcoal, form an excellent filter. The inside one, without a bottom, rests on three stones placed in layers of sand, charcoal, and coarse gravel. The water flows into the space between the barrels and forces its way through the gravel, charcoal, and sand into the inner barrel. Or they may be placed as in Fig. 81 and connected by a pipe. [Illustration: FIG. 81.] If the water is from a small spring gushing up out of the earth, perforate the bottom of the outer barrel with a number of holes, and leave the bottom to the inner barrel, which should be pierced with holes round its sides near the top. In both these filters draw off the water by a pipe running through the outer into the inner barrel. Allow eight pints per man in hot and six in temperate climates for cooking and drinking, and a similar amount for washing. In stationary camps allow 5 gallons per man for all purposes. LOG HUTS.