John Dalton Biography.

John Dalton was an English chemist and physicist, best known for his work on atomic theory and his work on colour blindness. Dalton was born in Cockermouth on the west coast of England into a family of Quakers. He worked at a Quaker school until 1793 when he moved to Manchester. Dalton learned a great deal of his scientific knowledge from a blind philosopher named John Gough, and from this Dalton was made Teacher of Mathematics and Philosophy at a college in Manchester until 1800, when he was forced to become a personal tutor due to lack of funds available at the college. Dalton began a meteorological diary in 1787, and made an estimated 200,000 weather observations during the remainder of his life. He also wrote a paper on the phenomenon of colour blindness, which had not been fully documented until Dalton's work was published. Daltonism became a common term for the condition at the time. He was then made Secretary of the Manchester Literary and Philosophical Society in 1800, and in 1801 he published papers on the constitution of mixed gases, the pressure of gases at different temperatures, and the evaporation and expansion of gases. In 1808 he published a book called A New System of Chemical Philosophy. This was his groundbreaking work on atomic theory based on five propositions. The first proposition was that all matter is composed of extremely small, indivisible particles called atoms. The second and third propositions state that atoms of each element are identical in size and mass, and that atoms cannot be created or destroyed. The fourth and fifth propositions are that elements combine to form chemical compounds in simple ratios, and that in chemical reactions atoms are combined, separated or rearranged. He also published the first table of atomic weights, as well as his work System of Chemistry. Dalton also lectured at the Royal Institution in London, and was awarded a fellowship in 1822. He never married and died in 1844 after suffering several strokes in the previous few years.