devised by him are first found in his note-book under the date September 6, 1803; and, under the same date there is a table of atomic weights, showing that, by this time, he had grappled with the fundamental problem—that of fixed "relative weights of the ultimate particles of bodies." For unknown reasons Dalton appended it, in a somewhat different form, to a paper "On the Absorption of Gases by Water," read before the Manchester Society in October, 1803, but not published till November, 1805. The table was added during the interval between presentation and publication. The summer of 1804, as Dalton himself tells us, was the crucial period of the investigation. The first part of the first volume of the "New System of Chemical Philosophy," published in 1808, gives the mature theory, while the second part of 1810 describes the chemical elements in detail. Dalton was now forty-four. And it is significant that, although he had lectured twice at the London Royal Institution, and in Glasgow and Edinburgh as well, the French Academy of Science recognized his merits six years[1] before any native body. In 1822, Dalton being fifty-six, the Royal Society honored itself by his election. Another decade elapsed ere Oxford conferred her D.C.L., on the occasion of the second meeting of the British Association, and he was sixty-eight when Edinburgh enrolled him among her honorary doctors. In 1833, the government took note of his services, and he received a civil list pension, increased afterwards in 1836, when the announcement was publicly made under dramatic circumstances by Sedgwick, at the Cambridge meeting of the British Association. "The imagination may picture, if it can," writes Roscoe, "the feelings of the son of the poor Eaglesfield handloom weaver as he sat in the Senate House of the University of Cambridge listening to this eulogium—the observed of all observers."[2] As Sedgwick remarked in his striking speech, "without any powerful apparatus for making philosophical experiments—with an apparatus, indeed, many of them might think almost contemptible—and with very limited external means for employing his great natural powers, he had gone straight forward in his distinguished course, and obtained for himself, in those branches of knowledge which he had cultivated, a name not perhaps equaled by that of any other living philosopher of the world."[3] Evidently, then, Dalton wrought under grave disadvantages. What were they?
We would all agree, I take it, that certain results of human activity must remain intimately personal, and that, as a consequence, they must vary from age to age, or diverge even among different peoples in the same epoch. Art and poetry, religion and, possibly, some portions of philosophy, can not well escape these very subtle contrasts. But, with
