Thomas Graham (December 21, 1805 - September 16, 1869) was a Scottish chemist. 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.