Chemistry / by George Wilson.

  • George Wilson
Date:
1859
Catalogue details

Licence: Public Domain Mark

Credit: Chemistry / by George Wilson. Source: Wellcome Collection.

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    'A 10 him with the'means of distinguishing simplS from compound bodies. Compound bodies may, accordingly, be defined to be those substances which, when subjected to heat, electri- city, light, mechanical agencies, or the vital forces, applied singly, or taken, where that is possible, together, suffer reso- lution or decomposition into two or more ingredients, which cannot, by subjection to the same processes, be similarly de- composed. Simple bodies, on the other hand, are those sub- stances which resist the decomposing power of the forces re- ferred to, and after the most protracted and repeated expo- sure to their influence, remain with every essential property altogether unchanged. 9. This exposure of substances to all known decomposing forces is spoken of by the chemist as their subjection to che- mical analysis, a word derived from the Greek am, up, or back to its sources, and Xvu, to loose, and signifying the separation or resolution of any complex or compound thing into its primary constituents, or ultimate elements, or the process by which that resolution is effected. Compound bodies admit of analysis—that is, every substance consisting of two or more ingredients admits of being analysed or decomposed into those ingredients, so that they can be shown apart. Simple bodies, on the other hand, consisting of but a single substance, are, in relation to chemical analysis, one and indivisible, and do not therefore admit of being analysed. 10. As analysis is the foundation of all chemistry, though by no means sufficient of itself to constitute it a science, it is of the utmost importance that at the very outset the mode in which it is applied to furnish a basis for the science should be appreciated. To illustrate this, the following examples are given:— 11. The most familiar of all liquids—water—was, from a very early period, considered an element or simple body. If a powerful electrical current, however, be sent through it, it analyses the water into two gases unlike each other, and un- like the water. The last, for example, at ordinary tempera- tures, is a liquid not itself combustible, and in which ordinary inflammables do not burn. The one of the gases into which it is resolved is called by the chemist hydrogen, and besides many other remarkable properties, is highly combustible. The other gas, named oxygen, causes a lighted body plunged into it to burn with much more brilliancy than in common air. Water, then, is a compound of two ingredients, hydro- gen and oxygen. The question now arises, Are the oxygen and hydrogen compounds of two or more constituents, as water is ? According to the present experience of chemists,
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