CANTON, John, an ingenious natural philosopher, was born at Stroud, in Gloucestershire, in 1718. Among those with whom he became acquainted in early life was Dr Henry Miles of Tooting, a learned and respectable member of the Royal Society, and of approved eminence in natural knowledge. This gentleman perceiving that Mr Canton possessed abilities too promising to be confined within the narrow limits of a country town, prevailed on his father to permit him to go to London. Accordingly he arrived at the metropolis in March 1737, and resided with Dr Miles at Tooting till the 6th of May following, when he articulated himself for the term of five years as a clerk to Mr Samuel Watkins, master of the academy in Spital Square. In this situation his ingenuity, diligence, and good conduct were so well displayed, that on the expiration of his clerkship in May 1742 he was taken into partnership with Mr Watkins for three years; which gentleman he afterwards succeeded in Spital Square, and there continued during his whole life. In 1744 he married Penelope, the eldest daughter of Mr Thomas Colbrooke, and niece to James Colbrooke, Esq. banker in London.
Towards the end of 1745, electricity, which seems early to have engaged Mr Canton's notice, received a very capital improvement by the discovery of the Leyden phial. This event turned the thoughts of most of the philosophers of Europe to that branch of natural philosophy;
and our author, who was one of the first to repeat and to pursue the experiment, found his assiduity and attention rewarded by many valuable discoveries. Towards the end of 1749 he was concerned with his friend, Mr Benjamin Robins, in making experiments in order to determine to what height rockets may be made to ascend, and at what distance their light may be seen. In 1750 was read at the Royal Society Mr Canton's "method of making artificial Magnets, without the use of, and yet far superior to, any natural ones." This paper procured him the honour of being elected a member of the society, and the present of their gold medal. The same year he was complimented with the degree of M. A. by the University of Aberdeen, and in 1751 he was chosen one of the council of the Royal Society.
In 1752 Mr Canton was so fortunate as to be the first person in England who, by attracting the electric fire from the clouds during a thunder storm, verified Dr Franklin's hypothesis of the similarity of lightning and electricity. Next year his paper entitled "Electrical Experiments, with an attempt to account for their several phenomena," was read at the Royal Society. In the same paper Mr Canton mentioned his having discovered, by a great number of experiments, that some clouds were in a positive, and some in a negative, state of electricity. Dr Franklin, much about the same time, made a similar discovery in America. This circumstance, together with our author's constant defence of the doctor's hypothesis, induced that excellent philosopher, immediately on his arrival in England, to pay Mr Canton a visit, and gave rise to a friendship which ever afterwards continued without interruption or diminution. In the Lady's Diary for 1756 our author answered the prize question that had been proposed in the preceding year. The question was, "how can what we call the shooting of stars be best accounted for; what is the substance of this phenomenon; and in what state of the atmosphere doth it most frequently show itself?" and the solution, though anonymous, proved so satisfactory to his friend, Mr Thomas Simpson, who then conducted that work, that he sent Mr Canton the prize, accompanied with a note, in which he said, he was sure that he was not mistaken in the author of it, as no one besides, that he knew of, could have answered the question. Our philosopher's next communication to the public was a letter in the "Gentleman's Magazine for September 1759," on the electrical properties of the tourmalin, in which the laws of that wonderful stone are laid down in a very concise and elegant manner. On the 13th December, in the same year, was read at the Royal Society, "An attempt to account for the regular diurnal variation of the Horizontal Magnetic Needle; and also for its irregular variation at the time of an Aurora Borealis." A complete year's observations of the diurnal variations of the needle are annexed to the paper. On the 5th November 1761, our author communicated to the Royal Society an account of the Transit of Venus, 6th June 1761, observed in Spital Square. Mr Canton's next communication to the Society was a letter addressed to Dr Benjamin Franklin, and read in February 1762, containing some remarks on Mr Delaval's electrical experiments. On the 16th December in the same year another curious addition was made by him to philosophical knowledge, in a paper entitled "Experiments to prove that water is not incompressible." These experiments are a complete refutation of the famous Florentine experiments, which so many philosophers have mentioned as a proof of the incompressibility of water. On St Andrew's day 1763 our author was for the third time elected one of the council of the Royal Society; and, on the 8th November in the following year, were read before that learned body his further "Experiments and observations on the com-
pressibility of water and some other fluids." The establishment of this fact, in opposition to the received opinion, formed on the hasty decision of the Florentine Academy, was thought to be deserving of the society's gold medal. It was accordingly moved for in the council of 1764; and after several invidious delays, which terminated much to the honour of Mr Canton, it was presented to him on the 30th November 1766.
The next communication of our ingenious author to the Royal Society was made in December 1763, being "An easy method of making a phosphorus that will imbibe and emit light like the Bolognian stone; with experiments and observations." When he first showed to Dr Franklin the instantaneous light acquired by some of this phosphorus from the near discharge of an electrified bottle, the doctor immediately exclaimed, "And God said, let there be light, and there was light." The dean and chapter of St Paul's having, in a letter to the president, dated 5th March 1769, requested the opinions of the Royal Society relative to the best and most effectual method of fixing electrical conductors to preserve that cathedral from damage by lightning, Mr Canton was one of the committee appointed to take the letter into consideration, and to report their opinion upon it. The gentlemen joined with him in this business were, Dr Watson, Dr Franklin, Mr Delaval, and Mr Wilson. Their report was made on the 8th of June following, and the method recommended by them has been carried into execution. The last paper of our author's which was read before the Royal Society was on the 21st December 1769, and contained "Experiments to prove that the Luminousness of the Sea arises from the putrefaction of its animal substances." In the account now given of his communications to the public, we have chiefly confined ourselves to such as were the most important, and which threw new and unexpected light on various objects in the philosophical world. Besides these, he wrote a number of papers both in earlier and in later life, which appeared in several publications, and particularly in the Gentleman's Magazine.
The close and sedentary life of Mr Canton, arising from an unremitting attention to the duties of his profession, and to the prosecution of his philosophical inquiries and experiments, probably contributed to shorten his days. The disorder into which he fell, and which carried him off, was a dropsy. His death happened on the 22d of March 1772, in the fifty-fourth year of his age.