Volume 1

Elements of the theory and practice of chymistry / Translated [By Andrew Reid] from the French of M. Macquer.

  • Pierre-Joseph Macquer
Date:
1775
Catalogue details

Licence: Public Domain Mark

Credit: Elements of the theory and practice of chymistry / Translated [By Andrew Reid] from the French of M. Macquer. Source: Wellcome Collection.

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    Theory of Chymistry. j becaufe in reality their feveral combinations with each other, the interchangeable coalitions that take place between them, conftitute the different natures of all other bodies ; which, as they refult from the union both of primary and fecondary principles, are properly entitled to the name of Compounds or Mixts. Before we enter upon the examination of Com¬ pound Subfiances, it is neceffary to confider the mod Simple ones, or our four Firft Principles, with fome attention, in order to difeover their chief properties. §. I. Of Air. Air is that Fluid which we conflantly breathe, hnd which encompafles the whole furface of the ierreftrial globe. Being heavy, like all other bodies, it penetrates into all places that are nor either abfolutely i'nacceffible, or filled with fome other body heavier than itfelf. Its principal property is to be fufceptible of condenfation and rarefadfion ; fo that the very fame quantity of Air may occupy a much greater, or a much fmaller fpace, according to the different (late it is in. Pleat and cold, or, if you will, the prefence and the abfence of the particles of Fire, are the mod ufual caufes, and indeed the mea- fu res, of its condenfation and rarefadion : for if a cer¬ tain quantity of Air be heated, its bdk enlarges in proportion to the degree of heat applied to it ; the confequence whereof is, that the lame fpace now contains fewer particles of Air than it did before. Cold again produces jud the contrary effed. On this property which Air has, of being coiP denfed and dilated by heat, its eladicity chiefly de* pends. For if Air were forced by condenfation into a lefs compafs than it took up before, and then expofed to a very condderable degree of cold, it would remain quite inadive, without exert- B 2 ing
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