Volume 1

The chemical pocket book, or Memoranda chemica, arranged in a compendium of chemistry / By James Parkinson, Hoxton.

  • Parkinson, James, 1755-1824.
Date:
1809
Catalogue details

Licence: Public Domain Mark

Credit: The chemical pocket book, or Memoranda chemica, arranged in a compendium of chemistry / By James Parkinson, Hoxton. Source: Wellcome Collection.

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    with sulphur an acid, as it seems, independent of oxygen; and with phosphorus a gas exceeding all others in inflammability. Water is an uninflammable fluid, and when pure, is trans- parent, colourless, and void both of taste and smell. Mr. Ca- vendish made the discovery that it is formed by the union of hydrogen and oxygen. It may therefore be considered as an oxide of hydrogen: oxygen and hydrogen appearing to unite, only in that certain proportion of which water is the result. The proof of its composition is thus obtained : water in a state of vapour, being made to pass over iron wire twisted and made red hot, the iron is oxidized, a considerable portion of the water disappears, and hydrogen gas is produced ; the iron depriving * the water of its oxygen, by which it becomes an oxide, whilst the hydrogen combining with caloric forms the hydrogen gas. Again, 15 parts of hydrogen gas being burnt in a close vessel with 85 parts of oxygen, water is formed, nearly of the same weight as the gases employed. It appearing that, at a tempe- rature loner than that of ignition, the attraction of the re- spective bases of the two gases to caloric, is stronger than their attraction to each other, which prevents their decomposition : but that at the degree of ignition, the attraction of the bases are stronger to each other than to caloric; hence they unite and form water, the caloric and light, their imponderable parts, being disengaged with flame. The composition of water by the ponderable part of these gases is beautifully evinced by the experiments of Dr. Pearson, by means of the electric spark. Water may be decomposed also by the influence of the galvanic pile. Fresh leaves also being immersed in water and exposed to the sun, the water will be de- composed : the oxygen gas will rise in bubbles, and the hydro- gen will enter into combination in the plant. The ingenious Mrs. Fulhame teaches that water is essential to the oxygenizement of combustible bodies. Thus, in the reduc- tion of metals, she supposes the water suffers decomposition, the reducing substance attracting the oxygen of the water, whilst