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=**John Dalton** =

__Introductory__
John Dalton was a famous scientist who is most recognized as the person to come up with the partical called the atom. He is the second to come up with an atomic theory after the Greek philosopher Democritus. His work was improved upon by many scientists to get today's modern atomic theory.

__Life__
Dalton (1766-1844) was born September 6, 1766 in Cumberland, England to a modest Quaker family. At the age of 12 he started teaching at his local village school. After teaching for 10 years at a school in Kendle he moved to a better teaching job in Manchester Academy. In Manchester he joined the Manchester Literary and Philosophical Society in which he had a more scientific environment to study in. He started to study meterology when influenced by a family friend, which led him to start his work on atoms. He then whent to teach in York. Dalton was afflicted with colorblindness.

__Work on Meterology__ In 1787 he started a journal on his study of the weather, which he maintained for 67 years until his death on July 27, 1844. In 1793 he published a book on meterology called //Meteorological Observations and Essays//. //Meteorological Observations and Essays// became Dalton's first definative work. Right after the publishment of this book he whent to Manchester. He taught natural philosophy and math while there. After Manchester he whent to work at a school in York in 1803 as a mathematics and chemistry teacher. __Work on Color Blindness__ Dalton wrote //Extraordinary Facts Relating to the Vision of Colours in// 1794 in which he propsed that colr blindness is caused by discoloration in the medium of the eyeball. Dalton himself wrote about his color blindness. His paper on color blindness was the first documented case and so color blindness is still sometimes called "Daltonism" because of this. But during his own lifetime his theory that discoloration caused color blindness lost credence. __Work on Atomics__ In 1808 John Dalton came up with the atomic theory. His theory said that all matter is composed of small, indivisible, and indestructible particles named atoms, atoms of one element are all exactly alike but are different from the atoms of other elements, when elements combine to form compounds their atoms combine in proportions such as one to one, two to one, and four to three. Dalton stated his theory in //A New System of Chemical Philosophy.// Although the Greek philosopher Democritus was the first person to come up with atoms, Dalton was the first to have a idea that atoms where different for each element and could be measured by weight. He calculated the weight of each atom by using percentages of composition compounds. Scientist had always wondered why a substance was alway proportionally the same no matter how it was formed or treated. Dalton solved this when he discovered that atoms form compounds in certain patterns with definate combining weights. Dalton then devised a table of drawings and symbols that represented each atom and its weight. Elements and their combinations as described in John Dalton’s //New System of Chemical Philosophy// (1808–1827). CHF Collections. __Later Years__ Dalton was president of Manchester Literary and Philosophical Society from 1817, until his death during which time he wrote 116 papers. These papers included the study of volumetric analysis, phosphates and arsenates, and how anhydrate when dissolved in water cause no change in the volume of the water. He often published his own papers when the Royal Society would not such as his papers: //On the Quantity of Acids, Bases and Salts in Different Varieties of Salts// and //On a New and Easy Method of Analyzing Sugar.// In 1822 he was elected to the Royal Society and in 1832 he accepted a Doctorate of Science from Oxford University. In 1833 the British government conferred on him a pension of £150, which was raised to £300 in 1836. He was a devote Quaker and often tried to deny these achievements but in the end usually accepted them because of his admirers and colleagues. All of Dalton's statements on atomic theory have been correct except for "Atoms cannot be subdivided, created, or destroyed into smaller particles when they are combined, separated, or rearranged in chemical reactions" which has been disproven with nuclear fission and fussion, and " All atoms of a given element are identical in their physical and chemical properties" because of the discovery of isotopes.

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