Inorganic chemistry / by Edward Frankland and Francis R. Japp.

  • Edward Frankland
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Inorganic chemistry / by Edward Frankland and Francis R. Japp. Source: Wellcome Collection.

    30/856 (page 4)
    sources. Thus water obtained from melting snow, from rain, from steam or from the artificial combination of its constituents, always consists of oxygen and hydrogen in the proportion of one part by weight of the latter to eight parts of the former. Again, common salt, whether obtained naturally from the mines of Cheshire or Poland, from the brine springs of Germany or America, from the salt lakes of Eussia or Australia, from sea water, or prepared artificially from its constituents, always consists of chlorine and sodium in the proportion of 35-5 parts of the former to 23 parts of the latter. When two bodies combine chemically or become united together by the chemical force, tJiey do so in fixed and definite 'proportions. The materials composing our universe are bound together by a force which, whether regarded as attraction or as pressure, pro- duces three sets of phenomena differing so much from each other as to lead to their being commonly referred to three of the distinct forces already mentioned. One of these is gravitation, which acts through distances inconceivably great. The second is cohesion, which acts only through spaces too small to be measured. The third is chemical attraction or chemical affinity which, like cohe- sion, also acts through distances too small to be measured, but which, as already mentioned, is distinguished, both from gravita- tion and cohesion, by producing a change of properties in the matter upon which it acts. Thus a lump of ice presses towards the centre of the earth, being pulled in that direction by the attraction of gravitation, which can be overcome by mechanical means. The lump of ice is made up of smaller pieces, for it can be broken up into an immense number of particles by mere mecha- nical effort, and thus cohesive attraction, like gravity, is overcome by mechanical means; but only partially, for each particle is made up of smaller particles still bound together by the same force. If, however,heat be applied to the ice, another well marked step in the conquest of cohesion is gained, and liquidity is induced—a condition in which the particles of the water move freely about and amongst each other. But even here cohesion is not completely vanquished, and the particles still cling to each other with a con- siderable amount of tenacity. By the application of a greater amount of heat, the complete conquest of cohesion is at last achieved. In the condition of steam, the particles of water no longer stick together: they are entirely freed from all cohesive