The development of the atomic theory.

  • Andrew Norman Meldrum
Date:
[1910-1911]
Catalogue details

Licence: In copyright

Credit: The development of the atomic theory. Source: Wellcome Collection.

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    been offered. They have already been mentioned in the second paper of this series. The first of these, coming direct from Thomas Thomson, is that Dalton discovered the composition of marsh gas and olefiant gas and was led thereupon to perceive the law of multiple proportions, and to devise his chemical theory as an explanation of the law. This may be called the inductive account. Again, Roscoe and Harden accept an account, offered by Dalton, which may be called the deductive one. Dalton had formed his diffusion hypothesis without considering the “ effect of difference of size in the particles of elastic fluids.” On consideration he found that “ the sizes must be different,” and thereupon he revised his diffusion theory. He then introduces the subject of the chemical theory :— “ The different sizes of the particles of elastic fluids being once established, it became an object to determine the relative sizes and weights, together with the relative number of atoms in a given volume. This led the way to the combination of gases,” etc. Objections to the purely inductive and deductive accounts. There being these two accounts, the inductive one and the deductive, of the origin of the theory, there arises the question, which comes nearer the truth? The Board of Education has recently committed itself to an opinion on this topic, in the course of its criticisms on the answers of students to its questions on chemistry. The particular question was :—“Give a short account of Daltons atomic theory, and discuss its value in explaining the laws of chemical combination.” Teachers of chemistry, to judge from the reference made to them, have been adopting Roscoe and
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