Purity of Water.

Purity of Water.

堪萨斯城,n . Kietsted先生在一篇窟er Supplies, which he read before the Association of Engineering Societies, gives the following on the seeming purity of clear water. Me says: The popular standards of the purity of water are clearness, tastelessness and colorlessness—three characteristics of water which will do more to allay popular suspicion and to prevent criticism than will any other properties, although they are neither definite nor conclusive proof of the purity and potability of a water, but are, in reality, less desirable qualities than are softness, freedom from putrescible organic matter and stability in storage. For instance, a colorless and perfectly clear ground water, especially when high in nitrates, will, if confined in an open reservoir, promote and support a more vigorous growth of organisms and may become fouled and polluted to a much greater extent than will many surface waters similiarly confined and either deeply colored by dissolved vegetable matter, or loaded with clay and sand in suspension. Likewise, a water meeting the requirements of the popular standard, but containing much lime and magnesia, particularly in the form of sulphates, is unfit for use in boilers and In houses, while a ground water containing peroxide of iron will cause much trouble and annoyance by the deposits of iron rust in the distribution pipes, and will prove very unsatisfactory in washing and in cooking. In other words, clearness, tastelessness and freedom from color, while, of course, excellent qualities in themselves, afford no criterion as to the purity of a water supply. Nevertheless, they often lead to the selection of inferior sources of supply.

There are many who tenaciously adhere to the use of cistern water for all domestic purposes, in preference to any public water supply, not only because of the superior softness of cistern water, but also because of the still prevailing sentiment that such water is the safest and purest water to drink. This sentiment will in time lessen its hold as our towns become more generally provided with sewerage and house plumbing, and as experience proceeds to demonstrate that the usual receptacles for the storage of rainwater and the methods of collecting it do not prevent its pollution.