Water and water-supply chiefly in reference to the British Islands. Surface waters / by D.T. Ansted.

  • Ansted, D. T. (David Thomas), 1814-1880.
Date:
1878
Catalogue details

Licence: Public Domain Mark

Credit: Water and water-supply chiefly in reference to the British Islands. Surface waters / by D.T. Ansted. Source: Wellcome Collection.

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    water inquiries.—(51) Analysis useless if all waters are thus characterised.— (52) Various ways of accounting for the presence of nitrogen in water.—(53) Analysis of water. Ignition method of determining organic contents.—(54) Per-manganate of potash method.—(55) Frankland and Armstrong's method.— (56) Ammonia method.—(57) Uncertainty of all methods.—(58) Metals present in water. — (59) Method of taking samples.— (60) Improvement of water hy filtration.—(61) Natural filtration.—(62) Mechanical filtration by descent.—(63) Lateral filtration.—(64) Material for filtering beds.—(65) Spencer's filtration by magnetic carbide.—(66) Chemical results with ordinary filtering material.—(67) Use of the lime process in improving hard water.—(68) Purification of rivers.— (69) Modes by which water is rendered unfit for domestic use.—(70) Sewage as a cause of pollution.—(71) Disposal of sewage.—(72) Water sometimes improved by continued pumping.—(73) Penetration of sewage matter into deep wells. 1. Water universally present.—Water is universally present, and forms an essential part of the earth, not only existing in large quantity in the ocean and on the surface of the land, hut always a constituent part of the rocks of which the earth's crust is composed, always a part of the atmosphere we breathe and that surrounds the earth, and always also a large and essential proportion of every organised being, whether animal or vegetable. It might seem unnecessary to offer lengthened prelimi- nary remarks as to its nature and uses, but it is desirable that know- ledge on the subject should be precise and accurate, and I commence this chapter with a few statements of fact to which the reader may find it useful to refer. 2. Composition of pure water.—Chemically pure water consists atomically of one atom of oxygen combined with two atoms of hydrogen (H2O), and volumetrically as one volume of oxygen combined with two volumes of hydrogen, the three volumes measuring after combination two volumes. By weight, the atom of oxygen weighs sixteen times that of hydrogen. Water, therefore, consists of eight parts by weight of oxygen to one of hydrogen. The composition and decomposition of water are accomplished with difficulty under ordinary terrestrial condi- tions, and cannot take place without the development of heat. The compound molecule of water once formed, is permanent under ordinary conditions, and behaves in a manner so like elementary substances, that it is regarded as a proximate element. 3. Properties of water. — The latent heat of water is 143° P. Thus, if one pound of water at the temperature of 143° be mixed with one pound of ice at the temperature of 32°, the ice will be melted, and the resulting water will have a temperature of 32°. The heat apparently lost is required to bring the frozen water back into a liquid state, and is called latent, having lain concealed in the ice. The boiling point of water, at the ordinary pressure on the earth's surface at the sea level (29-992 inches of mercury), is 212° F. When the pressure is dimi-