“It is impossible not to admire the ingenuity and talent with which Mr. Dalton has arranged, combined, weighed, measured, and figured his atoms; but it is not, I conceive, on any speculations upon the ultimate particles of matter, that the true theory of definite proportions must ultimately rest. It has a surer basis in the mutual decomposition of the neutral salts, observed by Richter and Guyton de Morveau, in the mutual decompositions of the compounds of hydrogen and nitrogen, of nitrogen and oxygen, of water and the oxymuriatic compounds; in the multiples of oxygen in the nitrous compounds; and those of acids in salts, observed by Drs. Wollaston and Thomson; and above all, in the decompositions by the Voltaic apparatus, where oxygen and hydrogen, oxygen and inflammable bodies, acids and alkalies, &c., must separate in uniform ratios.” It has been alleged that Davy in thus expressing himself offered a kind of factious opposition to the views of Dalton. In so far as they were _atomic_, this is possibly true, for Davy never brought himself to regard the fact of chemical combination occurring in definite proportions as admitting of the simple mechanical explanation of Dalton, which he considered too speculative. That, however, he did ample justice to Dalton’s merits ultimately will be seen from the terms in which he speaks of them on the occasion of the award to Dalton in 1826 of the first of the Royal medals. In one of his unfinished Dialogues, written shortly before his death, “On the Powers which act upon Matter and produce Chemical Changes,” he thus expresses himself:--