The elements of experimental chemistry / by William Henry.

  • Henry, William, 1774-1836.
Date:
1810
Catalogue details

Licence: Public Domain Mark

Credit: The elements of experimental chemistry / by William Henry. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

    123/570 (page 101)
    the term caloric, first proposed by Lavoisier, is now, there- fore, generally adopted to denote the cause of heat. Oc- casionally, however, in order to avoid too frequent a repe- tition of the same word, the term heat is still employed in .1 more extensive sense, to express not only the sensation which it usually denotes, but also some of the modifica- tions of caloric. Caloric, so far as its chemical agencies are concerned, may be chiefly considered under two views — as an an- tagonist to the cohesive attraction of bodies — and as con- curring with, and increasing elasticity. By removing the particles of any solid to a greater distance from each other, their cohesive atti-action is diminished; and one of the principal impediments to their union with other bodies is overcome. On the other hand, caloric may be in- fused into bodies in such quantity, as not only to overcome cohesion, but to place their particles beyond the sphere of cliemical affinity. Tims, in the class of substances called gases, the ponderable ingredient, whether solid or liquid, is dissolved in so much caloric, that in mechanical proper- ties the gases agree with the air of our atmosphere, and especially in being permanently elastic. Different bodies of this class do not in general unite by simple mixture. But if, of two gases, we employ either one or both in a state of great condensation, or compress their particles nearer to each other by any means, the gravitating matter of each unites, and forms a new compound. Thus hydro- gen and oxygen gases remain together in a state of mixtm^e, for any length of time, without combining; but if we force their particles into a state of contiguity by mecha- nical pressure, they unite and compose water. In many cases, also, when two bodies are combined together, one of which is fixed, and the other becomes elastic by union