Student's textbook of hygiene / [William James Wilson].

  • Wilson, William James.
Date:
[1915]
Catalogue details

Licence: Public Domain Mark

Credit: Student's textbook of hygiene / [William James Wilson]. Source: Wellcome Collection.

    148/316 (page 116)
    with wooden blocks 12 inches long and 1 inch thick, which dovetail into each other. The height of the ceiling should not be less than 9 feet, and need rarely exceed 12 feet. The lighting is influenced to a large extent by the proximity to and the height of neighbouring buildings and trees, but adherence to Gwilt’s rule, which provides 1 square foot of glass for every 100 cubic feet of room-space, will usually answer all requirements. If too much glass is inserted into the walls, the latter are weakened, and the cooling effect of the glass interferes with the proper warming and ventilation of the rooms. Windows should be situated in such a_ position in the wall as to afford an even distribution of light in the room, and their top should extend as near the ceiling as possible. Every house must be provided with an adequate supply of wholesome water. The main pipe entering the building from the outside is termed the “rising main,” and branches from this should supply the taps providing water for drinking and culinary purposes. At the top of the house the rising main discharges into a cistern, the flow being regulated by a ball- valve situated at the end of the pipe. Water-pipes are usually made of lead, and for an ordinary dwelling-house a pipe of 4-inch internal diameter is a common size. From its ductile quality, lead adapts itself to the turns and bends to which a pipe is subjected. Certain waters have the power of dis- solving lead, and this plumbo-solvency, we have already seen, is due to the organic acids contained in supplies from moor- land areas. To guard against the danger of Lead-Poisoning among the consumers of such water, neutralization of the acids is the first desideratum, and the second is the use of pipes made of other materials than lead. To prevent contact of the water with the lead, a lead pipe may be lined with tin or glass, but it is difficult to make proper joints in such pipes. Where iron pipes are used, they must be protected against corrosion either (1) by immersion at a temperature of 600° F. in Angus Smith’s solution, consisting of 4 parts of coal tar, 3 parts of prepared oil, and 1 part of paranaphthaline; or (2) by Barff’s process, which consists in the production of a coating of black magnetic oxide in the lining of the pipe.