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

Date:
1893
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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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    4. ESSAY ON A MANNER OF DETER- MINING THE RELATIVE MASSES OF THE ELEMENTARY MOLECULES OF BODIES, AND THE PROPORTIONS IN WHICH THEY ENTER INTO THESE COMPOUNDS. By A. AVOGADRO * I. MGAY-LUSSAC has shown in an interesting Memoir (Mdmoires de la Socidtd d'Arcueil, Tome II.) that gases always unite in a very simple pro- portion by volume, and that when the result of the union is a gas, its volume also is very simply related to those of its components. But the quantitative proportions of sub- stances in compounds seem only to depend on the rela- tive number of molecules t which combine, and on the number of composite molecules which result. It must then be admitted that very simple relations also exist between the volumes of gaseous substances and the numbers of simple or compound molecules which form * Journal de Physique, LXXIII. (1811), pp. 58-76. t [Avogadro has been accused of inconsistency in his use of the term molecule, but a careful perusal of his paper will show that he uses it with its qualifying adjectives quite consistently, as follows:— MoUcule (translated molecule ) without qualification means in modern chemical phraseology either atom or molecule. MoUcule intigrante (translated integral molecule) means molecule in general, but is usually applied only to compounds. Molicule constituante (translated constituent molecule) is em- ployed to denote the molecule of an elementary substance. MoUcule iUmentaire (translated '' elementary molecule ) stands for the atom of an elementary substance.]
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