Water and water-supplies : and unfermented beverages / by John Attfield.

  • John Attfield
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Water and water-supplies : and unfermented beverages / by John Attfield. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    ally, in so far as they bring the organic impurities in the water and the oxygen of the air into closer contact and, therefore, under good conditions for that chemical attack on each other which results in the entire alteration of both into a minute quantity of harmless nitre added to the water and a small quantity of carbonic acid which gives desired aeration to the water. Such a filter, therefore, is an actual fire-grate. A pound of animal or vegetable matter burned in a fire-grate is converted by the air drawn into the fire into several pounds of carbonic acid gas, etc., which pass up the chimney. A pound of animal or vegetable matter contained in water passing through a filter is burned in that filter by the air dissolved in the water into several pounds of carbonic acid, etc., which pass into the water. It is interesting to add that just as much heat is given out in the one operation as in the other. In the fire-grate the burning is rapid and concentrated and the warmth can be felt ; in the filter it is slow and diffused over such a vast mass of water that the best thermometer is not delicate enough to detect it. Analysis of Water.—The analysis of water, or, rather, of the substances which may be present in the water, involves a series of operations of so special and technical a character that no useful purpose would be served by describing them in a Handbook intended solely for the general public. To ascertain the nature and amount of each of the dissolved solids will occupy the whole time of an expert chemist for several days. Such a complete analysis is, however, only required by certain manufacturers, brewers, water companies and owners of mineral springs. The ordinary mineral sub- stances in drinking waters not being impurities, the chemist analysing water for potability does not take notice of them unless they are present in abnormal proportions. It is to the organic, that is, animal or vegetable matter present, that he devotes his attention. Even an analysis from this point of view occupies sjveral hours. He ascertains the total amount of dissolved solids present; tests for the substances termed nitrites, finds out how much nitre is in [H. 12.] G
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