Sunday, December 20, 2009
Thomas Graham was born in Glasgow on December 21, 1805 the the eldest of seven children of a merchant father. After attending preparatory school and high school he started classes at the university of Glasgow in 1819, where he studied under Thomas Thompson. He remained there for seven years taking an M.A. in 1826. His father wanted him to go into the Scottish church, but Thomas showed an aptitude for mathematics and science and against his father's wishes he commenced on a career in science.
Graham was a lecturer in chemistry at the Mechanics Institution in Glasgow and then he was appointed professor of chemistry at Andersonian University in Glasgow. It was at this point that he was able to devote more time to experimentation and the seven years he spent at Andersonian were busy. In 1837 he was appointed professor of Chemistry at London University (now University College, London) where he occupied the chair until 1855 when he succeeded Sir John Herschel as Master of the Mint and remained in that positon until he died.
Graham is best remembered for his discovery that under the same temperature and pressure the rate of effusion of a gas is inversely proportional to the square root of its atomic mass. A demonstration of this can be found here. Basically this law means that the smaller the atomic mass of the gas the faster it will diffuse. Graham was awarded the Keith prize in 1834 by the Royal Society of Edinburgh for this discovery.
Graham is also remembered for his invention of dialysis. Between 1861 and 1864 Graham, while he was studying the ability of dissolved substances to pass through a membrane, noticed that substances that crystallized well like salt passed well through the membrane and substances that did not crystallize like gelatin did not. He distinguished these two classes of substances as crystalloids and colloids. This discovery led to the dialysis that is done on kidney patients today.
Graham is also remembered for is characterization of phosphates in solution. For all of these discoveries Graham was awarded the Copley medal of the Royal Society in 1862.
Graham died on September 16th, 1869.
Williamson, A.W.; Obituary in Nature, Volume 1, (1869) p. 20-22
Obituary in the Proceedings of the Royal Society; Volume 18 (1870) p. xvii-xxvi
Obituary in the Lancet; Volume 2 (1869) p. 456-457
Plimer, Robert Henry Aders; Practical Organic and Biochemistry Chemistry; Logmans, Green and Company; 1920