Thomas Graham is known for his studies on the behavior of gases, which resulted in his formulation of two relationships, both since becoming known as "Graham's laws," the first regarding gas
diffusion, and the second regarding gas
effusion. In the former case, Graham deduced that when measured repeatedly under the same conditions of pressure and temperature, the rate of diffusive mixing of a gas is inversely proportional to the square root of its density, and given the relationship between
density and
molar mass, also inversely proportional to the square root of its
molar mass. In the same way, in the latter case, regarding
effusion of a gas through a pin hole in to a vacuum, Graham deduced that the rate of
effusion of a gas is inversely proportional to the square root of its molar mass. These two are sometimes referred to as a combined law (describing both phenomena). In applied areas, Graham also made fundamental discoveries related to
dialysis, a process used in research and industrial settings, as well as in modern health care. Graham's study of
colloids resulted in his ability to separate colloids and crystalloids using a so-called "dialyzer", using technology that is a rudimentary forerunner of technology in modern
kidney dialysis machines. These studies were foundational in the field known as
colloid chemistry, and Graham is credited as one of its founders. He also proposed the
association theory which claimed that the substances such as
cellulose or
starch that we now know are polymers are composed from smaller molecules hold together by unknown forces. It remained the most popular explanation until
Hermann Staudinger's
macromolecular theory of 1920s. ==Honours, activities, and recognition==