To Purify Water.—When water in wells or other receptacles smells bad, suspend in it lumps of charcoal in a basket or net, so that they can be re moved and replaced at intervals.
To Clarify Water. — Water in springs, wells, and streams often be comes muddy after heavy rains, and the water of some streams always holds a large amount of liquid mud and other impurities in solution. In such cases it becomes important to clarify the water to make it more pal atable and attractive, and this is es pecially the case when filters are used, as otherwise the filter soon clogs up and becomes useless.
Alum is a universal agent for pre cipitating impurities in suspension or even in solution. It is very common ly employed along the Missouri and Mississippi rivers and other muddy streams.
To quickly clarify a pitcher of drinking water, tie a lump of alum to a string and swing it about in the water. The sediment will settle.
Or, for larger quantities, use 1 tea spoonful of pulverized alum to 4 gal lons of drinking water. Stir the water before putting in the alum. After the water has settled, draw it off in such a way as not to disturb the sediment. A tablespoonful of the alum will set tle the contents of a hogshead of water. The alum itself, if too much is not used, will settle and be carried off in the sediment.
Or lime is recommended, used in the form of certain salts of lime, either chloride, nitrate, or bicarbonate of lime, or caustic lime. Use 1 part of any of these salts of lime to 1,000 parts of water.
Or sulphate of alumina is recom mended for clarifying water contain ing vegetable or animal matter. The formula is as follows: Bisulphate of alumina (neutral solution), 1 ounce; water, 435 gallons.
Or dissolve 2 ounces of saltpeter in 1 quart of warm water, and throw the solution into the cistern or well.
Or, to purify putrid water: Water, 1 pound; sulphuric acid, 8 drops. Mix and filter through charcoal.
Or water, 8 gallons; powdered alum, 1 ounce. Dissolve with agita tion, then allow it to rest for twenty four hours, decant into another ves sel, and add a solution of carbonate of soda until it ceases to produce a precipitate.
Or instead of alum add 7 or 8 grains of red sulphate of iron, then proceed as before.
Or add a little aqueous chlorine to the foul water.
Or arrange a suitable pipe to the end of a pair of bellows (double bel lows are best), and force the air through the water for some time, then allow it to settle for use.
Water Filters.—The ordinary house hold appliances for filtering water are rarely preventives of disease. Such filters are not ordinarily cleansed often enough, and become receptacles for disease germs instead of means of prevention.
The better practice is to boil drink ing water from twenty minutes to half an hour when there is danger of contamination. The following are a number of devices that may be rec ommended to make muddy or other wise contaminated water clear for ap pearance sake. It must be borne in mind, however, that these processes and all other filters merely strain the water in a mechanical way, and do not remove or destroy the germs of contagious diseases. These cannot be destroyed without boiling the water, as just recommended: Cistern Filter. — The rainfall col lected in cisterns is a valuable source of water supply in localities where it is difficult or costly to drive a well, and also in regions where the water is hard. Rain water is soft, and hence especially adapted to laundry pur poses.
Cisterns should be carefully screened with wire netting to exclude insects, toads, and other vermin, and should be so arranged as not to admit sur face water. They should be kept scrupulously clean, the first rainfall being excluded to allow accumulated dust and dirt to be washed off the roof. The average rainfall through out the United States on a. roof sur face 40 feet square will supply five or six barrels a day, which is sufficient for an average family.
Cisterns are often built in two cora partments, one above the other, with a third compartment between, which should be a box containing filtering material, such as broken stones, peb bles, charcoal, and sand. A sponge is sometimes placed at the outlet. Thus water may be received in the upper compartment while the lower compartment is being emptied and cleansed; then the contents of the up per part may be strained through the filter until the lower part is filled and the upper part, in turn, is renovat ed. The box containing the filtering material should be detachable, and this material should be occasionally cleansed or replaced.