Thomas Graham (December 21, 1805 - September 16, 1869) was a Scottish chemist. He became a student at the University of Glasgow where he developed an interest in chemistry. He received his M.A. in 1826. He later became a professor of chemistry at numerous colleges, including the Royal College of Science and Technology and the University of London. He founded the Chemical Society of London in 1841. He is remembered for his studies on the diffusion of gases which resulted in "Graham's Law", which states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass. And also for his discovery of dialysis, which is used in many medical facilities today, was the result of Graham's study of colloids. He was able to separate colloids and crystalloids using a "dialyzer", the precursor of today's dialysis machine. This study initiated the scientific field known as colloid chemistry, of which Graham is credited as the founder. His final position was as the Master of the Mint, where he stayed for 15 years until his death. He was the last person to hold that position. He died in 1869 at the age of 63.