MSU Gallery of Chemists' Photo-Portraits and Mini-Biographies

* John Dalton

1766-1844

Dalton developed the atomic theory of matter as a consequence of his researches on the behaviour of gases. He is responsible for the law of partial pressures - that the total pressure of a mixture of gases is the sum of the pressures exerted by each gas independently. He also found that gases expand as their temperature is raised; he demonstrated the solubility of gases in water, and that the composition of the atmosphere is approximately constant to an altitude of 15,000 feet. He developed the laws of definite and multiple proportions. A complete scientist, Dalton also made important observations on the aurora borealis, rain, trade winds, and color blindness. The atomic mass unit, the Dalton, is named for him.