Royal Society's Honours. 13 



torily determine their weight and magnitude ; and for this 

 purpose it will be necessary to solve at least three questions : — 

 1. Is Mr. Dal ton the inventor of the Atomic Theory — is he the 

 discoverer of those peculiar laws of combination and decom- 

 position upon which it immediately rests ? — 2. Has Mr. Dalton 

 essentially contributed to its development — was it useless and 

 barren in the hands of its inventor, and was he the first to pro- 

 mulgate its importance as bearing upon the general laws of 

 chemical science — did he first show its practical applications, 

 and render it available to the manufacturer and to the arti- 

 san ? — 3. Has he disclosed any new views connected with the 

 applications of the theory to the more abstract branches of 

 chemical science ? 



Of these questions, the first is the most essential to Mr. 

 Dalton' s claims ; but it unfortunately happens that they stand 

 negatived upon the most direct of all evidence, and that Mr. 

 Higgins is decidedly the discoverer of those principles of com- 

 bination upon which one part of the atomic theory is founded. 

 Upon him the grave has closed, and he is no longer able to 

 defend his personal pretensions. Had he been alive, I much 

 doubt whether sufficient effrontery could have been mustered 

 to venture upon the step I am discussing. Let us now 

 look a little into the matter, and listen first to the President 

 himself. — 



" That the proportions in compound gases are definite, has 

 long been generally acknowledged; but Mr. Higgins is, I 

 believe, the first person who conceived that, ivhen gases com- 

 hined In more than one iiroportion, all the proportions of the 

 same element were equal ; and he founded this idea, which was 

 made public in 1789, on the corpuscular hypothesis that bodies 

 combine jmrticle with jyarticle^ or one with two, or three, or a 

 greater number of particles.'" Sir Humphry then adds, " Mr. 

 Dalton, about 1802, adopting a similar hypothesis, apparently 

 without the knowledge of what Mr. Higgins had written, 

 extended his views (Mr. Higgins's) to compounds in general*." 



Let us now hear Mr. .Higginsf : '* These considerations," 



* Elements of Chemical Philosophy, p. 107. 



•I- Experiments and Observations on the Atomic Theory and Electri- 

 cal Phenomena. 



