Memoir of Thomas Graham. 



It would be difficult to find in the history of science a charac- 

 ter more simple, more noble, or more symmetrical in all its parts 

 than that of Thomas Graham, and he will always be re- 

 membered as one of the most eminent of those great students 

 of nature, who have rendered our Saxon race illustrious. He 

 was bom of Scotch parents in Glasgow m the year I8O0, and m 

 that city, where he received his education, all his early life was 

 passed/ In 1837 he went to London as Professor of Chemistry 

 in the newly established London University now called Uni- 

 versity College, and he occupied this chair until the year 18o5, 

 when he succeeded Sir John Herschel as Master of the Koyal 

 Mint, a post which he held to the close of his life. His death, 

 on the 16th of September last, at the age of sixty, though oc- 

 casioned by a severe cold, was really the wearing out ot a con- 

 stitution enfeebled in youth by excessive labor, voluntarily un- 

 dertaken and courageously borne, that he might devote his hte 

 to scientific study. As with all earnest students, that life was 

 uneventful, if judged by ordinary standards ; and the records 

 of his discoveries form the only materials for his biography. 

 Although one of the most successful mvestigatore of I'hysicai 

 Science, the late Master of the Mint had not that felicity of lan- 

 guacre or that copiousness of illustration, which added so much 

 to the popular reputation of his distinguished contemporary, 

 Faraday; but his influence on the progress of science was not 

 less marked or less important Both of these eminent men 

 were for a long period of years best known to the Enghsh pub- 

 lic as teachers of Chemistry, but their investigations were 

 chiefly limited to physical problems; yet, although both culti- 

 vated the border ground between Chemistry and Physics, they 

 followed wholly different lines of research. Whfle l_araday was 

 so successfully developing the principles of electrical action, 

 Graham with equal succesl was investigating the laws of molec- 

 ular motion. Each followed with wonderful constancy, as well 

 as skill, a sinde line of study from first to last, and to this con- 

 centration of power their great discoveries are largely due. 



One of the eariiest and most important of Graham s ij^^estiga- 

 tions, and the one which gave the direction to l^^^, subsequent 

 course of study, was that on the diftusion of gases. It had already 

 been recognized that impenetrability in its ordinary sense is not 

 as was formeriy supposed, a universal quality of matter. Dalton 

 had not only recognized that aeriform bodies exhibit a positive 

 tendency to mix, or to penetrate through each other, even m op- 

 .* Prom the Proceedings of the American Academy of Arts and Sciences, vol. 



