The hygiene of air and water : being a popular account of the effects of the impurities of air and water, their detection, and the modes of remedying them / by William Procter.

  • Procter, William.
Date:
1872
Catalogue details

Licence: Public Domain Mark

Credit: The hygiene of air and water : being a popular account of the effects of the impurities of air and water, their detection, and the modes of remedying them / by William Procter. 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.

    64/94 (page 58)
    tionis made of Permanganate of Potash ; or Condy's (crimson) fluid, which is a similar solution, is diluted— either of them is the test solution. Take half a pint or more of the water to be examined, previously acidified by the addition of a few drops of hydrochloric (muriatic) acid, or about 12 drops of sulphuric acid (oil of vitriol) diluted with five parts of water, add the test solution, drop by drop, whilst stirring, until a faint pink tinge is perceptible. Every fifteen minutes the water is to be looked at, and as the colour disappears, a few drops more of the test solution cautiously added, and this is to be so continued until the colour remains permanent for half an hour. All the organic matter is then destroyed (oxidised), and the quantity of solution required to effect this gives a rough estimate of the matter originally in the water. The change of colour is better observed by placing the vessel upon a sheet of white paper before a window, and looking down at the paper through the liquid. If the solutions are accurately prepared, and the process conducted carefully, the exact quantity of (oxidisable) organic matter can be estimated, and an opinion forme of the fitness of the water for dietetic purposes. Although the operation is a delicate one, the estimation may be made with some degree of accuracy by the following method:—Dissolve two grains of pure Permanganate of Potash in rather more than half a pint (10£ oz.) of distilled water; ten minims of this solution yield 5^5 °f a grain of oxygen. Fill an apothecary's minim measure with this solution, and proceed with a known quantity of water in the manner previously described : and then read