John Dalton (1766-1844) and his contemporary Sir Humphrey Davy could not have been less alike. Davy was a gifted communicator with an international profile; Dalton was tongue-tied and uncomfortable south of Cheshire. But both made historic discoveries, and where Davy left us Faraday, Dalton gave us Joule.
JOHN Dalton, a weaver’s boy, began his teaching career at fifteen, helping his elder brother to run a Quaker school in Kendal. He deepened his education by contributing maths problems to The Ladies’ Diary,* and reading scientific works to Kendal’s distinguished natural philosopher John Gough, who was blind, in exchange for lessons in Latin and Greek.
At twenty-seven, Dalton took up a post as a lecturer in mathematics in Manchester.* His interests included colour-blindness, from which he suffered himself and of which he gave the first detailed description; the pressure and expansion of gases, contributing Dalton’s Law of Partial Pressures and tutoring James Joule;* and meteorology, climbing and mapping Cumbria’s mountains for his measurements.
In 1805, Dalton made history with the first scientific theory of the atom and relative atomic weights, and in 1808 added Dalton’s Law of Multiple Proportions.* He was rewarded with Fellowships at the Royal Society and the French Academy of Sciences, and his work remains the basis of modern chemistry.
* See our story The Ladies’ Diary.
* As he was a Quaker and not a member of the Church of England, Dalton was barred by the Test Acts from holding office in Britain’s only recognised Universities, Oxford and Cambridge. However, other Dissenters had set up a rival, private and very distinguished Academy at Warrington in Cheshire, which by the time Dalton joined had reformed as Manchester New College. A few years after the repeal of the Test Acts in 1871, the college settled in Oxford, and is now called Harris Manchester College.
* Visit Wikipedia for Dalton’s Law of Partial Pressures. James Joule (1818-1889) was a brewer who made historic contributions to the science of heat and energy; the SI derived unit of energy, the joule, is named after him.