Dalton's Atomic Theory

Abstract

WITH reference to the communications from the authors and from the reviewer of the “New View of the Origin of Dalton's Atomic Theory,” published in NATURE for May 14, I beg leave to offer the following remarks. The most serious difficulty which the reviewer advances against the new view, seems to be that Dalton, in his manuscript lecture to the Royal Institution in 1810, states that, as a consequence of an idea respecting elastic fluids which occurred to him in 1805, “it became an object to determine the relative sizes and weights, together with the relative number of atoms in a given volume”; whereas in one of his note-books, under date September 6, 1803, a table of atomic weights is given. The reviewer says:— “The authors notice this conflict of statement, but get rid of it by assuming 1805 to be a clerical error for 1803.” In regard to these conflicting dates, I beg to draw attention to a passage which appears to have escaped the vigilance both of the authors and of the reviewer, and which seems to tell strongly in favour of the clerical error theory. In the preface to Part I. of Dalton's “New System of Chemical Philosophy” (1808), the author, writing of himself, says:— “In 1803, he was gradually led to those primary laws, which seem to obtain in regard to heat, and to chemical combinations, and which it is the object of the present work to exhibit and elucidate. A brief outline of them was first publicly given the ensuing winter in a course of lectures on natural philosophy, at the Royal Institution in London, and was left for publication in the journals of the Institution; but he is not informed whether that was done.” I do not think there is any room for reasonable doubt that this passage refers, amongst other things, to the same idea as that stated in the manuscript lecture to have occurred to Dalton in 1805. In any case the date 1803 is definitely settled by the sentence referring to the lectures at the Royal Institution, since we know that Dalton's lectures were begun there on December 22, 1803 (compare Roscoe and Harden's “New View, &c,” p. 61). It ought to be possible to place this matter beyond all doubt if the notes stated by Dalton to have been left for publication in the journals of the Royal Institution are forthcoming.