John Dalton

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John Dalton (6 September 1766–27 July 1844) was a British chemist and physicist. He was born in Cumberland to a Quaker family. He is best known for his discoveries in atomic theory. He also made the first important studies of color blindness.

John Dalton
Dalton collecting marsh gas by Ford Madox Brown about 1890. Mural in Manchester Town Hall

Dalton's atomic theory


Dalton's Atomic theory is a scientific theory about atoms. Dalton made the theory to explain why the elements would combine in certain ways[1] The idea of atoms was already known at the time, but not widely accepted. Dalton's theory of atoms was based on actual observation. Before this, ideas about atoms were based more on philosophy.

His theory stated that:

  • Everything is made from atoms
  • Atoms cannot be divided
  • Atoms can not be made or destroyed
  • Chemical reactions are made when atoms are moved around, put with other atoms or taken away from a group of other atoms
  • Atoms of the same element are the same, because they have the same atomic mass.
  • Atoms can only be joined in special ratios (see Law of definite composition)

Further readings

  • Claus Bernet: John Dalton (1766-1844), in: Biographisches-bibliographisches Kirchenlexikon, 31, 2010, 309-332.


  1. Latscha, Hans Peter (2011). Allgemeine Chemie - Chemie-Basiswissen I. Springer. p. 3. ISBN 978-3-642-17522-0.

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