Dalton, John

Chemist. Born in Eaglesfield, Cumbria, England. After 1781 he became assistant in a boarding-school kept by a cousin in Kendal. In 1787 he commenced a meteorological journal that he continued all his life, recording over 200,000 observations about the atmosphere. In 1793 he was appointed professor of mathematics and science in New College, Manchester.
One of the leading early scientists, his contributions to the field are numerous. Because he and his brother both were afflicted with color blindness, he was the first to describe the condition--which came to be known as Daltonism--in 1794. His chief physical researches were focused on mixed gases, the force of steam, the elasticity of vapors, and the expansion of gases by heat. Named for him, Dalton's Law was established following his study of partial pressures.

In chemistry he worked on the absorption of gases, and his atomic theory interpreted the laws of chemical combination and the conservation of mass, establishing a new basis for all quantitative chemistry.

Dalton never married, and he remained a man of quiet demeanor and simple habits, reflecting his Quaker beliefs.