Canton was born in Middle Street Stroud, Gloucestershire, the son of a weaver John Canton (b. 1687) and Esther (née Davis). At the age of nineteen, under the auspices of Dr Henry Miles, he was articled for five years as clerk to Samuel Watkins, the master of a school in Spital Square, London, with whom at the end of that time he entered into partnership.
In 1750 he read a paper before the Royal Society on a method of making artificial magnets, which procured him election as a fellow of the society. In 1751 he was a recipient of the Copley Medal "On account of his communicating to the Society, and exhibiting before them, his curious method of making Artificial Magnets without the use of Natural ones." He was the first in England to verify Benjamin Franklin's hypothesis of the identity of lightning and electricity, and he made several important electrical discoveries.
In 1762 and 1764 he published experiments in refutation of the decision of the Florentine Academy, at that time generally accepted, that water is incompressible. In 1768 he described the preparation, by calcining oyster-shell with sulphur, of the phosphorescent material known as Canton's phosphorus. His investigations were carried on without any intermission of his work as a schoolmaster. He died in London aged 53 of dropsy.
He was the recipient of letters from Thomas Bayes, which were then published by the Royal Society.
This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Canton, John". Encyclopædia Britannica (11th ed.). Cambridge University Press.