Thomas Graham

Thomas Graham was the Glasgow-born chemist who gave his name to Graham’s law and founded a whole branch of science, colloid chemistry. His studies of how gases and liquids spread shaped modern chemistry, pointed the way to the kidney dialysis machine, and even to the separation of isotopes.

A Glasgow chemist

Graham was born in Glasgow in 1805, the son of a prosperous textile manufacturer who wanted him to become a minister. Defying his father, he entered the University of Glasgow at fourteen, and there fell in love with chemistry. After a spell at Edinburgh he returned home, and in 1830, aged just twenty-five, became professor of chemistry at Anderson’s College in Glasgow, part of the city’s long story in education and science.

Graham’s law and colloids

His great discovery was that the rate at which a gas spreads is inversely proportional to the square root of its density, the principle we now call Graham’s law. He went on to study how substances pass through membranes, coined the word ‘colloid’, and is counted as one of the founders of colloid chemistry. That same work on separating substances through a membrane was the direct ancestor of the kidney dialysis machine.

Master of the Mint

By the 1840s Graham was acknowledged as the leading British chemist of his day, and the first president of the Chemical Society. In 1854 he was appointed Master of the Mint, a post once held by Sir Isaac Newton, and he was the last man ever to hold it before the office was abolished.

A Glasgow grave

Graham died in London in 1869, and his body was brought home to be buried at Glasgow Cathedral. A statue was later raised in his honour among the great figures that ring George Square.