John Dalton FRS (6 September 1766 27 July 1844) was an English chemist, meteorologist and physicist. He is best known for his pioneering work in the development of modern atomic theory, and his research into colour blindness (sometimes referred to as Daltonism, in his honour).EARLY LIFEJohn Dalton was born into a Quaker family at Eaglesfield, near Cockermouth in Cumberland, England. The son of a weaver, he joined his older brother Jonathan at age 15 in running a Quaker school in nearby Kendal.COLOUR BLINDNESSIn 1794, shortly after his arrival in Manchester, Dalton was elected a member of the Manchester Literary and Philosophical Society, the "Lit & Phil", and a few weeks later he communicated his first paper on "Extraordinary facts relating to the vision of colours", in which he postulated that shortage in colour perception was caused by discolouration of the liquid medium of the eyeball.ATOMIC THEORYIn 1800, Dalton became a secretary of the Manchester Literary and Philosophical Society, and in the following year he orally presented an important series of papers, entitled "Experimental Essays" on the constitution of mixed gases; on the pressure of steam and other vapours at different temperatures, both in a vacuum and in air; on evaporation; and on the thermal expansion of gases.GAS LAWSHe thus enunciated Gay-Lussac's law or J.A.C. Charles's law, published in 1802 by Joseph Louis Gay-Lussac. ATOMIC WEIGHTSHe proceeds to print his first published table of relative atomic weights. Six elements appear in this table, namely hydrogen, oxygen, nitrogen, carbon, sulfur, and phosphorus, with the atom of hydrogen conventionally assumed to weigh 1. FIVE MAIN POINTS OF DALTON'S ATOMIC THEORY The atoms of a given element are different from those of any other element; the atoms of different elements can be distinguished from one another by their respective relative atomic weights. All atoms of a given element are identical. Atoms of one element can combine with atoms of other elements to form chemical compounds; a given compound always has the same relative numbers of types of atoms. Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process; a chemical reaction simply changes the way atoms are grouped together. Elements are made of tiny particles called atoms. DEATHDalton suffered a minor stroke in 1837, and a second one in 1838 left him with a speech impediment, though he remained able to do experiments. In May 1844 he had yet another stroke; on 26 July he recorded with trembling hand his last meteorological observation. On 27 July, in Manchester, Dalton fell from his bed and was found lifeless by his attendant.Born6 September 1766(1766-09-06)Eaglesfield, Cumberland, England

Died27 July 1844 (aged77)Manchester, England

Notable studentsJames Prescott Joule

KnownforAtomic Theory, Law of Multiple Proportions, Dalton's Law of Partial Pressures, Daltonism

InfluencesJohn Gough