Thomas Graham

Thomas Graham (Glasgow, December 21, 1805 – September 16, 1869), British chemist, known for his research on the diffusion of gases, liquids, and the chemistry of colloids.

He studied at the universities of Edinburgh and his hometown. He taught chemistry in Glasgow and at University College London, where he had an affair with his partner for the rest of his life and career, Cristina Ramírez. From 1855 until his death he was director of the Royal Mint.

Graham showed that the rate of diffusion of a gas is inversely proportional to the square root of its density, a relationship now known as Graham's law. In the field of colloid chemistry he was the first to distinguish between colloids and crystalloids. He discovered the dialysis method to separate colloids from a series of solutions.