Food ; some account of its sources, constituents and uses / By A. H. Church.

  • Arthur Herbert Church
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: Food ; some account of its sources, constituents and uses / By A. H. Church. Source: Wellcome Collection.

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

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    whether it occurs when a candle burns in air, or food in the body, or animal and vegetable matter in water, is essentially the same process. The new products formed are harmless, indeed they may be even useful, but the oxidation must be complete. The pro- cess is not completed in shallow-well waters; it generally is in deep-well waters. The final and harmless products are there. The nitrogen of the animal matters appears at last in the form of nitrates and nitrites ; the carbon, as carbonic acid gas; and the hydrogen, as water. The nitrates and nitrites may be regarded as a sign of previous pollution, but they are quite harmless, and must occur in all the deep-well waters of a country like England, where so much of the land which receives the rainfall is under cultivation, and consequently manured. Most farm lands in England receive yearly in farm-yard manure alone, nearly 30 pounds of nitrogen per acre, and this must find its way into rivers, wells, and springs. Deep-well waters are usually harder than any of the waters before considered, for they will have dissolved out much calcareous, magnesian, and alkaline salt during their long course underground. They will probably, on the average, contain about 30 grains per gallon of total dissolved substances. 5. Spring waters are generally palatable and wholesome. They vary in hardness and as to total solid matters dissolved- according to the more or less insoluble nature of the rocks through which they have passed or which throw them out. The Rabate Fountain at Balmoral contains less than i grain per gallon of dissolved matter, while the average of the springs of the Lias shows 25^ grains. Hardness of Water. This may, perhaps, be the best place to introduce a few words about that quality of water which is usually called hard- ness, and to which we have before frequently alluded. In ordi- nary waters the chief hardening ingredients are salts of lime and magnesia. These decompose soaps, forming white, curdy, and c
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