Early Life
Born in 1766 in Eaglesfield, Cumberland, into a poor Quaker weaver's family, Dalton received his early education from his father and a local Quaker teacher. Remarkably, he began running his own school at just 12 years old. At 15 he joined his brother in running a Quaker school in Kendal, where he was mentored by the blind philosopher John Gough, who inspired his lifelong interest in meteorology and science. In 1793 he moved to Manchester to teach mathematics and natural philosophy.
Major Discoveries
- 01Modern atomic theory: all matter consists of tiny indivisible atoms
- 02Atoms of the same element are identical in mass; different elements differ
- 03Law of multiple proportions
- 04Dalton's law of partial pressures of gases
- 05First table of relative atomic weights (1805)
- 06Described colour blindness ('Daltonism') from his own experience (1794)
Famous Experiments
- 01Kept daily weather records for 57 years — over 200,000 observations
- 02Measured how gases mix and dissolve in water, leading to partial pressures
- 03Analysed compounds of carbon and oxygen and of nitrogen and oxygen to find simple whole-number ratios
Awards & Honors
- 01Royal Medal of the Royal Society (1826, first ever recipient)
- 02Fellow of the Royal Society (1822)
- 03Foreign member of the French Academy of Sciences (1830)
Legacy
Dalton gave chemistry its atomic foundation, making it possible to understand reactions as rearrangements of atoms. The unit of atomic mass, the dalton (Da), is named after him. Over 40,000 people attended his funeral in Manchester.
Fun Facts
- 01He used circles with symbols to represent atoms — early chemical notation
- 02He asked that his eyes be examined after death to study his colour blindness
- 03DNA analysis in 1995 confirmed he had deuteranopia
- 04He never married, saying he had no time