Dalton is best known for his formulation of the atomic theory, which clarified our understanding of how atoms combine to form compounds, and how atoms may form new combinations during chemical …John dalton frs (/ ëˆdéëlté™n /;5 or 6 september 1766 †27 july 1844) was an english chemist, physicist, and meteorologist whose work laid the foundations of modern atomic theory and stoichiometric …Dalton's most significant contribution to science was his development of modern atomic theory.In 1803, he proposed that all matter is composed of small, indivisible particles called atoms.Although a schoolteacher, a meteorologist, and an expert on color blindness, john dalton is best known for his pioneering theory of atomism.He also developed methods to calculate atomic weights and …