Timeline Friday 21 October 1803

Events on Friday 21 October 1803 1

• 1803 John Dalton outlines atomic theory First table of relative atomic weights presented Chemist John Dalton presented a table of relative atomic weights to the Manchester Literary and Philosophical Society, part of the modern atomic theory he was developing. He proposed that each element consists of identical atoms of a characteristic weight, and that compounds form in fixed ratios of these atoms. His theory became a foundation of modern chemistry.