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The motion of an actual chemically uniform matter – ancient as it is – fully corresponds to the childish view, widely held even up to Lavoisier, that the chemical affinity of two bodies depends on each one containing a common third body. (Kopp, Entwickelung, p. 105.)[245]

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How old, convenient methods, adapted to previously customary practice, become transferred to other branches and there are a hindrance: in chemistry, the calculation of the composition of compounds in percentages, which was the most suitable method of all for making it impossible to discover the laws of constant proportion and multiple proportion in combination, and indeed did make them undiscoverable for long enough.

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The new epoch begins in chemistry with atomistics (hence Dalton, not Lavoisier, is the father of modern chemistry), and correspondingly in physics with the molecular theory (in a different form, but essentially representing only the other side of this process, with the discovery of the transformation of the forms of motion). The new atomistics is distinguished from all previous to it by the fact that it does not maintain (idiots excepted) that matter is merely discrete, but that the discrete parts at various stages (ether atoms, chemical atoms, masses, heavenly bodies) are various nodal points which determine the various qualitative modes of existence of matter in general – right down to weightlessness and repulsion.

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Transformation of quantity into quality: the simplest example oxygen and ozone, where 2:3 produces quite different properties, even in regard to smell. Chemistry likewise explains the other allotropic bodies merely by a difference in the number of atoms in the molecule.

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The significance of names. In organic chemistry the significance of a body, hence also its name, is no longer determined merely by its composition, but rather by its position in the series to which it belongs. If we find, therefore, that a body belongs to such a series, its old name becomes an obstacle to understanding it and must be replaced by a series name (paraffins, etc.).

  1. H. Kopp, Die Entwickelung der Chemie in der neueren Zeit, 1. Abt., München, 1871, S. 105.