John Dalton (6 September 1766–27 July 1844) was a British chemist and physicist. He was born in Cumberland to a Quaker family. He is best known for his discoveries in atomic theory. He also made the first important studies of color blindness.
Dalton's Atomic theory is a scientific theory about atoms. Dalton made the theory to explain why the elements would combine in certain ways[1] The idea of atoms was already known at the time, but not widely accepted. Dalton's theory of atoms was based on actual observation. Before this, ideas about atoms were based more on philosophy.
His theory stated that: