The water supply of barracks and cantonments / by G.K. Scott Moncrieff.

  • Moncrieff, G. K. Scott.
Date:
1896
Catalogue details

Licence: Public Domain Mark

Credit: The water supply of barracks and cantonments / by G.K. Scott Moncrieff. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    of soap in washing, although it is not so good for cooking as soft. It is not necessarily unwholesome for drinking, although for horses it is not so good as soft water. Hence, in barracks, it is customary to utilize rain water, which is very soft, from roofs for washing purposes, and have a separate supply for drinking (see Chapter X.). The relative hardness of water is calculated on what is known as Clark’s scale, 1 grain of carbonate of lime per gallon being the unit. Thus water of 10° hardness will waste as much soap as would be wasted by pure water with 10 grains of chalk per gallon added to it. Now as every grain of chalk wastes 8 grains of soap, every gallon of water at 10° hardness will waste 80 grains of soap. Thus if every person uses 6 gallons of such water per diem, this means 480 grains of soap per diem, or 25lbs. of soap per annum, wasted. The saving in Glasgow resulting from the use of soft Loch Katrine water has been estimated at £36,000 per annum. An ordinary good water should not have more than 15’ total hardness and 5° permanent hardness. Average London water is said to contain 15° of hardness, Edinburgh water 5°, Glasgow 0-S°, Manchester l-8°, and Liverpool 2° to 3°. Soft water is by some supposed to be less healthy than hard, but the statistics of the towns above mentioned do not support this idea. The method of estimating the hardness varies in different countries. In France each degree of hardness indicates 1 part by weight of carbonate of lime per 100,000 parts of water; in Germany 1 part of lime per 100,000 of water. Thus 1 English degree = 0'S German = L4 French. The French scale is commonly used among analysts. Hard water is said to be objectionable for cooking, as the lime tends to harden the fibre of meat when boiled ; and it is also said to take longer than soft water for the infusion of tea. On the other hand, the tea is said to be better in flavour with hard water. In laundry work the use of soda neutralizes the effect of hardness, as the soda (carbonate of sodium) precipitates the calcium salts and prevents the destruction of the soap. The removal of hardness will be subsequently considered, in treating of the details of purification. Metallic Pollution. The metals which have been found in water are for the most part iron, zinc, and lead. Other metals may be also found, but not in ordinary cases.