Biographical Information
- Born on September 6, 1766, in Eaglesfield, Cumberland County, England
- Son of a Quaker weaver
- Suffers from colour blindness
- Was educated at a Quaker school, where he taught at age 12
- Moved to Kendal in 1781 to teach at another school
- Went to Manchester in 1793 to teach at the New College and as a private tutor
- Died in Manchester on July 27, 1844 at age 78
Major Contributions
- First work, Meteorological Observations and Essays, was published in 1793, with very little interest
- Most important scientific contribution was his atomic theory, which he first advanced in 1803 and published in 1808 in the book A New System of Chemical Philosophy
- It states that all elements are made of tiny particles called atoms
- All atoms of an element are identical
- The atoms of an element are different from the atoms of another element
- Atoms of different elements can combine to form more complex substances
- Also discovered Dalton’s Law, where the total pressure exerted by a mixture of gases is equal to the sum of the pressures of the separate gases
Historical and Social Context
- Before discovering the atomic theory, he already has notable scientific reputation
- Invited to deliver courses at the Royal Institution in London
- Made a fellow of the Royal Society in 1822 and awarded the society’s gold medal in 1826
- Became one of eight foreign associates at the French Academy of Sciences in 1830
- In 1833, he was conferred a pension of 150 pounds, which was raised to 300 pounds three years alter
- Many chemists and biochemists use the unit Dalton in honour of him to denote one atomic mass
- Rated 32nd most influential person in history by Michael H. Hart in his book The 100
