ON THE AIR AND WATER OF TOWNS. 6f 



of this kind which happen in country places ; the well is put in a garden or 

 back yard.and often verylittle defended. The number of cases of sickness from 

 these causes is, I am inclined to think, greater than is believed. Although 

 it is not my province to examine the matter in a medical point of view, I have 

 had opportunities of perceiving, partly alone, partly in conjunction with me- 

 dical men, that there are constantly occurring cases which seem to be brought 

 on or aggravated by the state of the wells. The impurities which occur in 

 the country wells are chiefly organic matter. This is known by its decom- 

 position, a small amount producing a disagreeable smell and taste, and at the 

 same time a dullness in the water, so that it makes itself known to us by three 

 of our senses. If it is merely surface-water somewhat cleared by standing still, 

 it will make itself known by depositing a great amount of green vegetation, 

 when a little is allowed to stand in a clear bottle. The remedy for this evil 

 is not difficult, and probably very well known. It consists in defending the 

 entrance of water into the well in such a manner that the Avater shall be fil- 

 tered. If a well be badly supplied with filtering material, the use of sand will 

 make a good filter, placed round the well so that the water may pass down 

 and bubble up like a spring from the bottom. In the country the organic 

 impurity may be easily removed in this manner ; but in the town, or near 

 cesspools and similar places, the impurity, if removed, leaves behind it an 

 unfortunate result, — the formation of nitrates and increase of chlorides, and 

 often of other salts, chiefly of lime. This water may be perfectly clear and 

 often is brilliant ; and some people do not discover a nauseous taste until the 

 solution of salts becomes so strong as to give the water the sluggish flow of 

 oil. So little is the taste of good water known in a town, that water, which 

 to an ordinary taste was nauseous and almost painful, has been in use for 

 years by people who might rationally have been expected to know better. 



This complete nitrification and thorough removal of the organic matter 

 occurs chiefly in town wells, the complete change being much less frequent 

 in the country; the cause of this lies, no doubt, in the slower and more 

 thorough filtration, and therefore the more elaborate cleansing when passed 

 through a hard soil, and in the removal of the rain-water by surface-drainage 

 or by sewers before it is allowed to weaken the solutions by being absorbed 

 into the soil. The amount of organic matter which is removed or altered in 

 this way is surprising, and the power of efi'ecting this transformation is a 

 most important and valuable part of the functions of a soil. Of course 

 the same change takes place in country places, in gardens, for example, well 

 ornamented and not well drained, where the water has much organic matter 

 in solution and stands long on the soil. This change takes place very close 

 to the cesspool or to the source of the flow of organic matter, and at a very 

 short distance water may be found containing very little besides inorganic 

 salts. Very near a sewer, in one of the worst streets in Manchester, I found 

 sand which was almost free from organic matter, although the drain had given 

 way and was allowing the sand to absorb whatever it could. The same ob- 

 servation was made on the sand of a churchyard in which burials Avere very 

 frequent, showing the great advantage of a porous soil in removing offensive 

 materials by an agency within itself, preventing the corruption of the atmo- 

 sphere to an extent greater or less, according as the powers of the soil are 

 under- or over- taxed. 

 I As an agent for purifying towns this oxidation of organic matter is one of 

 I the most marvellous, we might almost say, and necessary. If the impure 

 organic matter were taken underground by the natural flow of Avater, the 

 , state of the subsoil would become pestilential in the extreme, and towns could 

 I not be inhabited without such careful drainage as we have never yet seen ; 

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