The elements of experimental chemistry (Volume 1).

  • Henry, William, 1774-1836.
Date:
Nov. 1814
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Licence: Public Domain Mark

Credit: The elements of experimental chemistry (Volume 1). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    operation. With heat, Light also, as a repulsive agent, is fre- quently associated; and electricity belongs to the same class >qf powers. But as the action of electricity consists, chiefly, in effect- ing the disunion of chemical compounds, I have removed it from that place in the system, which seems naturally to belong to it. For before we can understand the general laws of electro-chemic- al agency, it is necessary to know something of oxygen and a few of the inflammable bodies ; nor can the theory of the excitation of galvanic electricity be made at all intelligible, without this previ- ous knowledge. The phenomena of heat, and the laws deduced from them, conduct us naturally to the great source of that fluid, which will be traced to a class of bodies agreeing, in mechanical properties, with the air of our atmosphere, and called airs or gases. These gases, Ave shall find, consist partly of gravitating matter, and partly of an extremely subtile fluid, which impresses on our or- gans the sensation of heat, and is called caloric* When the pon- derable ingredients, usually called the bases, of these gases, com- bine together, or with other bodies, caloric is given out and new compounds are generated. It is on the possession or absence of the property of decomposing one of them, oxygen gas, that a comprehensive division has been made of bodies into combustible and incombustible. The latter, however, it appears probable, are such, only in consequence of being already combined with oxygen. Hence we might divide all the variety of substances into oxygen and inflammable matter ; and of these, the last mentioned, it ap- pears not improbable from Mr. Davy's discoveries, will turn out to be universally metallic. The next class of bodies, that claim our attention, includes those compounds, which are formed cither by the union of the sim- ple gases or of their bases. Thus oxygen and nitrogen gases compose atmospheric air; and hydrogen and oxygen water. Ni- trogen and hydrogen, by their union, afford ammonia ; and with this fluid the fixed alkalis are naturally associated. The detail of properties belonging to the alkalis and earths, is, indeed, a neces- sary preliminary to that of the acids, the most important quality of which is, that they constitute, with the alkalis and earths, the extensive class of neutral salts. The consideration of the bases of the alkalis and earths has been made to follow that of the bod- • Light and electricity are probably, also, constituents of the gases.