Foundations of the atomic theory : comprising papers and extracts by John Dalton, William Hyde Wollaston, M. D., and Thomas Thomson, M. D. (1802-1808).

Date:
1899
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Licence: Public Domain Mark

Credit: Foundations of the atomic theory : comprising papers and extracts by John Dalton, William Hyde Wollaston, M. D., and Thomas Thomson, M. D. (1802-1808). Source: Wellcome Collection.

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    best. Let little more nitrous gas than is sufficient to form nitric acid be admitted to the oxygenous gas; let no agitation be used; and as soon as the diminution appears to be over for a moment let the residuary gas be transferred to another tube, and it will remain without any further diminution of consequence. Then T2 * * * * 7F of the loss will be due to oxygen.—The transferring is necessary to prevent the nitric acid formed and combined with the water, from absorbing the remainder of the nitrous gas to form nitrous acid. Sulphuret of lime is a good test of the proportion of oxygen in a given mixture, provided the liquid be not more than 20 or 30 per cent, for the gas (atmospheric air); if the liquid exceed this, there is a portion of azotic gas imbibed somewhat uncertain in quantity. Volta’s eudiometer is very accurate as well as elegant and expeditious: according to Monge, 100 oxygen require 196 measures of hydrogen; according to Davy 192 ; but from the most attentive observations of my own, 185 are sufficient. In atmospheric air I always find 60 per cent, diminution when fired with an excess of hydrogen; that is, 100 common air with 60 hydrogen, become 100 after the explosion, and no oxygen is found in the residuum ; here 21 oxygen take 39 hydrogen. 2. Of the Weight of the Aqueous Vapour Atmosphere. I have, in a former essay, (Manchester Mem. vol. 5. p. 2, page 559.) given a table of the force of vapour in vacuo for every degree of temperature, determined by experiment; and in the sequel of the essay, have shown that the force of vapour in the atmosphere is the very same as in vacuo, when they are both at their utmost for any given temperature. To find the force of aqueous vapour in the atmosphere, therefore, we have nothing
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