Foundations of the molecular theory : comprising papers and extracts / by John Dalton, Joseph-Louis Gay-Lussac, and Amedeo Avogadro.

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Foundations of the molecular theory : comprising papers and extracts / by John Dalton, Joseph-Louis Gay-Lussac, and Amedeo Avogadro. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    hydrogen and one of nitrogen, and its density compared to air is 0.596. But if we suppose the apparent contrac- tion to be half of the whole volume, we find 0.594 for the density. Thus it is proved, by this almost perfect con- cordance, that the apparent contraction of its elements is precisely half the total volume, or rather double the volume of the nitrogen. I have already proved that oxygenated muriatic gas is composed of 300 parts of muriatic gas and 100 of oxygen gas. Admitting that the apparent contraction of the two gases is half the whole volume, we find 2.468 for its density, and by experiment 2.470. I have also assured myself by several experiments that the proportions of its elements are such that it forms neutral salts with the metals. For example, if we pass oxygenated muriatic gas over copper, there is formed a shghtly acid green muriate, and a little oxide of copper is precipitated, because the salt cannot be obtained perfectly neutral. It follows from this that in all the muriates, as in oxygenated muriatic acid, the acid reduced to volume is thrice the oxygen. It would be the same for carbonates and fluorides, the acids of which have for equal volumes the same saturation capacity as muriatic acid. We see, then, from these various examples, that the contraction experienced by two gases on combination is in almost exact relation with their volume, or rather with the volume of one of them. Only very slight differences exist between the densities of compounds obtained by calculation and those given by experiment, and it is probable that, on undertaking new researches, we shall see them vanish entirely. Recalling the great law of chemical affinity, that ever7 combination involves an approximation of the elementary molecules, it is difficult to conceive why carbonic oxide gas should be lighter than oxygen. Indeed, that is the