Avogadro and Dalton: the standing in chemistry of their hypotheses / by Andrew N. Meldrum, D.SC ; with a preface by Francis R. Japp.

  • Meldrum, Andrew Norman, 1876-1934.
Date:
1904
Catalogue details

Licence: In copyright

Credit: Avogadro and Dalton: the standing in chemistry of their hypotheses / by Andrew N. Meldrum, D.SC ; with a preface by Francis R. Japp. Source: Wellcome Collection.

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

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    AVOGADRO'S HYPOTHESIS IN RELATION TO PURELY CHEMICALMETHODS. IVas fruchtbar is/, allciii ist tea//;-. —GoiCTinc. The fundamental hypothesis of chemistry is Avogadro's hypothesis. The molecule, whose relative weight is deter- mined on the basis of this hypothesis, is the unit of chemical change. The atom is a subordinate idea ; it is deduced from the idea of the molecule. The atom is the smallest part of an element which is found to enter into the composition of a molecule. In this definition of the molecule, and in the subordinate definition of the atom, there is the possibility of a synthetic philosophy of chemistry which, moreover, can be brought into co-ordination with physics. The laws of com- bination in multiple and in reciprocal proportions appear as deductions from the idea of the atom. Not as a believer in atoms and molecules, but from a purely critical standpoint, Ostwald takes another view from that just given, of the relation between the molecule and the atom. He holds that modern chemistry is a product of two hypotheses—the atomic hypothesis due to Dalton, and the molecular hypothesis due to Avogadro.^ This is partly a historical question, and, as such, it will be considered in the second part of this essay. For the present, one obvious objection to Ostwald's view may be pointed out: the unity of chemistry is at stake, just as it was when the supposition was made that inorganic and organic chemistry were two independent sciences.^ The view that the mole- cular and atomic hypotheses are independent of one another involves the possibility of molecular and atomic weights which have no connection with one another. If the independence of the molecule and the atom is a tenable doctrine, it has never been worked out to its logical conclusion. Reduced to practice, its results are likely to be cumbrous and highly ' Ostwald, pp. 146-150. Tliiij was Dumas' suggestion. Klassiker, 30, 59.