Manual of practical hygiene / ed., F. S. B. François De Chaumont, M. D., F. R. S.

  • Edmund Alexander Parkes
Date:
1883
Catalogue details

Licence: Public Domain Mark

Credit: Manual of practical hygiene / ed., F. S. B. François De Chaumont, M. D., F. R. S. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    46/806 page 22
    22 WATER. nitrates. Shallow well-water is always to be viewed with suspicion ; it is the natural point to which the drainage of a good deal of surrounding land tends, and heavy rains will often wash many substances into it.^ The question may arise as to what should be considered a shallow, and what a deep well. In the Rivers Pollution Commissioners' Sixth Report all the shallow wells examined are less than 50 feet deep; most of the deep wells more than 100 feet deejj. Any well less than 60 feet deep that does not pass through an impermeable stratum, such as stiff clay or hard rock, must be classed as a shallow well. The following table is given by the Elvers Pollution Commissioners — Wholesome \ 2. Deep well-water, . \ ^'^ Palatable. I 3. Upland surface-water ] , , , ^ , ^^ Sus icions \ rain-water, . | moderately palatable. ^ \ 5. Surface water from cultivated land, . . 1 Dano-erous i ^' I^^^^^'^^^^^' which sewage gains access, \ palatable. \l. Shallow well-water, . . . . ) Sub-Section II.—Characters and Classification op Drinking Waters. The general characters of good water are easily enumerated. Perfect clear- ness ; freedom from odour or taste; coolness; good aeration; and a certain degree of softness, so that cooking operations,, and esj)ecially of vegetables, can be properly performed, are obvious proj)erties. But when we attempt a more complete description, and assign the amounts of the dissolved matters which it is desirable should not be exceeded, we find considerable difference of opinion, and also a real want of evidence on which to base a satisfactory judgment. Still an hygienic classification or enumeration of potable waters, based on such facts as are generally admitted, will be useful. A division of waters^ used for drinking into four classes has been adopted in this work:— 1. Pure and wholesome water. 2. Usable „ 3. Suspicious „ 4. Impure The waters belonging to the first and second class may be used; those of the third, or suspicious class, should be well filtered before distribution, and, if possible, should be again filtered in the house. A purer source should also be obtained if possible, and sources of sewage contamination ascertained and prevented. The waters of the fourth class should be entirely disused, or only be used when a better source is not procurable, and means of purification should then be systematically resorted to. Sub-Section III.—Origin of the Impurities in Drinking Water. The origin of the impurities in water may be conveniently referred to four heads, viz. :—(1) Substances derived from the source; (2) Substances added during the flow of the waters in rivers, canals, aqueducts, or other conduits ; (3) Impurities caused by storage in reservoirs or tanks; and (4) Substances added during distribution from reservoirs either in pipes or water barrels, or in house cisterns. 1 Dr. Cameron (DvMin Journal of Medical Science) cites a case where sooA. and bad water were obtained from different levels in the same well. Similar results have been observed elsewhere ; see analysis of water from a well at Fareham, Report on H ygiene .1. ^1/. J). L ejwrts vol. xxi. In these cases both samples were impure, but the water from the bottom o<- the well contained a great excess of salts, due probably to infiltration from the tidal waters of tta- neighbouring river. ^i'^i^ Report, p. 129. i
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