CISTERNS. In all countries subject to a lack of water at certain seasons of the year, resort is had to cisterns or tanks for holding a supply. Few persons appreciate the large amount of water which may be supplied by the roofs of ordinary farm buildings, for family and stock uses. Throughout the West, frona the Falls of St. Anthony north, to Vicksburg south, the average rain-fall is almost thirty inches. Thus the roof of a barn thirty by forty feet, would give annually 400 hogsheads of water; a hogshead holds sixty-four pailfuls. Thus we have 25,600 pailfuls, sufficient to afford nearly four pailfuls each, per day, to twenty animals, the year round. A hogshead is about eight and a half cubic or solid feet. A hole or cistern two feet two inches square and the same depth, will hold one hogshead of water; one twice that size and depth will hold eight hogsheads; one eight feet each way will hold sixty-two hogsheads; one ten feet each way will hold 120 hogsheads. A round cistern or well four feet in diameter and six feet deep, will hold over forty-six hogsheads of water; one of the same diameter and nine feet deep will hold about fifty-five hogsheads; one twelve feet deep, same diameter, about ninety three hogsheads. The foregoing form a con venient basis from which to calculate. The roofage of a good dwelling will usually collect about as much rain-water as the barn roof, por tions of which, if desired, may be collected in a reservoir in the upper story, for convenient use in bathing tubs, etc. Cisterns at the house, for drinking and culillary purposes, should be deeper and narrower than at the barn, say ten to twelve feet, (not a great depth from which to raise it,) that the water may be cooler and better settled. They should also be divided by partition walls through the middle, made of soft porous brick, without mortar, and with some style of filter near the bottom, through which the water may all pass before being used. Into one of these apartments the water should be conducted from the eaves, but should be drawn out as used from the other; the one into which the water falls being a few inches deeper, that all impurities and sediment may settle to the bottom, and not be allowed to get into the other apartment, by which process there will always be clear water for use. Where the soil is clay, the wooden cis tern is unnecessaiy, and will cost more than three times as much as the labor and material to cement the cistern in the best manner, by plaster ing the cavity, which is the best and cheapest mode of making cisterns water-tight. One coat is sufficient if the cement is good, and the mor tar well mixed. A practical mason states the following: So much depends upon both cement and sand, that one can not direct any certain proportion of either to be used, unless we can give the material a practical test. Mixtures of
one-fourth cement to three-fourths sand may make better mortar than some other qualities of cement when using equal proportions of both ; so that we must be governed more by the work ing of the material when well mixed, by its tenacity, readiness to slip off the trowel, and quickness to set, than by measurement on pro portions of the two substances without the work ing test. Measure each and test the mixture till you find the proper proportion, then continue to use those proportions. A coat of good cement mortar directly on the earth, one-quarter of an inch in thickness, is generally better than greater thickness; if too thick it is liable to crack in drying and settling. It is sometimes necessary to add two coats of mortar, where spots of the earth wall are softer by removal of stones or roots, etc. In cases of cracks, mix a thick wash of cement and sand, and apply it to the cracks with a brush. To make good cement mortar, the sand and cement should be thoroughly and carefully mixed and incorporated before any water is applied; and as soon as practicable after it is wet it should be used. Cement work should not be exposed to frost for at least three or four months after being finished, as freez ing would destroy it before it is thoroughly set. In relation to reservoirs: low places in the fields, reservoirs for water, may be easily made in a dry time, to which water will flow during heavy rains. These should he as deep as possible, to prevent excessive evaporation; for instance, an excavation two feet deep will evaporate in about one third the time that one four feet deep will, and the deeper the tank the slower the evapora tion from a given surface on account of the cooler temperature of the water. For the same reason the sides should be as steep as possible, say at about an angle of 45°, or a slope of one to one, except just where stock go to drink. Here it may be less sloping and should be thickly graveled, or otherwise protected from poaching, so the water will not become muddy. When there is underdrained land on the farm the out fall of water should always be led into the tank, since it will furnish a large supply of cool, pure water, a most important consideration. So where a single line of tile runs through a field; in depressions where the tile comes nearer the surface than in others, cemented cisterns holding a good supply may be made, and the water easily pumped from thence to the surface. Indeed, we have seen many situations, where the water may thus be brought quite to the surface, so stock may drink at will, the outflow being carried away in tiles laid at a lower depth than that at which the water enters.