There is always the possibility that the purification of municipal water supplies may be incomplete or that contamination may ensue from private wells or other auxiliary supplies into water mains forbidden in New York ex cept with the apnroval of the Board of Health or may be contamination may ensue from sewage or other subterranean pollution in cities, so that pathogenic bacteria may still exist in public water supplies, as they may exist in well waters and in all other kinds of raw waters. Such menace to health may •be avoided, however, by the installation of ap proved purification processes in private dwell uting reservoirs at Colles Cordoba and Via monte, which cover an area of four acres and have a capacity of 13,500,000 gallons. Buenos Aires now has a good water supply. Argentina is enforcing hygienic regulations in all of its coast cities.
Rio de Janeiro obtains its waters from mountain sources. The waters are conducted into receiving reservoirs and then are carried 33 miles from their sources through conduits to distributing reservoirs, in the course of which there is some purification.
The foregoing will suffice to show the world wide interest now being taken in water supplies and the researches of scientists and efforts that have been made and are being put forth by all progressive communities to secure for them selves pure and wholesome water for potable and other domestic rurposes.
Enough has already been said to demonstrate the vital importance of water supplies to com munities and to individuals. In this article the problems involved in the construction of water works have not been discussed for they are engineering problems and do not come within its scope. The larger and more important problems of water supplies, however, halve been presented at some length in order that readers of the ENCYCL"PLUIA ings, hotels, hospitals, schools, offices, factories, etc.
The matter is of such transcendent import ance that the Treasury Department of the United States Government called together a corps of distinguished specialists in 1914, and they formulated standards of purity for water to be consumed by the public, which was being supplied by common carriers in interstate com merce.
The article is contributed in the hope that it may awaken a deeper interest in the subject than that taken by individuals and communi ties which have suffered most seriously from unwholesome water supplies in the past.