CAMUS, CHARLES ETIENNE LEWIS, a celebrated French mathematician, was born at Cressy in Bric, on Elie 1.,th of August, 1699, and was tlic. son of Etienne Cannes, a surgeon of that place. At a very curly age he dinplayed a great attachment to inechailical pursuits, and while his companions were amusing themselves at play, he •ao often found constructing sonic 111..(21 with no other instrument hut a knife. Before the eleventh year of his age, he felt such a passion for mathematical learning, that he entreated his parents to send him to the college at Paris ; but from the narrowness of their cir cumstances, they at first hesitated about the prudence of such a step ; and it was oniy from a well founded confi dence in the wisdom and talents of 011ie son, that they at last resolved to send him to the college of Navarre.
In a short time Cannes became one of the best scho lars at the college ; and at the end of two years he was able to give lessons in mathematics, and thus to defray all the expellees of his education.
Under the care of the celebrated Varignon, Camila applied himself to the study of the higher branches of mathematics, and he at the same time directed his atten tion to the subjects of civil and military architecture, mechanics, and astronomy. I lis know ledge of these subjects gained him the acquaintance and friendship of M. De Cotte, Couplet, and Cassini, and paved the way for his introduction into the academy of sciences. In the year 1727, that learned body having proposed as the prize subject, " The best method of roasting vessels," Camus entered the lists, and had the good fortune to be among the number of those whose memoirs on this sub ject were published by the academy in the Rccucil des Prix. • In consequence of this proof of his talents, Cainus ob tained, on the 13th August 1727, the place of adjunct mechanician, vacant by the promotion of M. Pitot. the year 1728, he wrote a memoir on accelerated motion by living forces, a subject which was then agitated with much heat. On the 16th December, 1730, the academy of architecture appointed him professor of that science ; and in 1733, he was honoured with the office of secretary to the same academy. Ile obtained the degree of asso• ciate to the academy of sciences on the 18th of April 1733. On this occasion the celebrated Clairaut was his competitor, and appeared upon counting the votes to have a majority of one in his favour. It v. as imagined. however, that some mistake had been committed in tak ing down the votes, and in consequence of this suspicion. the king, at the request of the academy, nominated both. the candidates.
In the year 1736, Camus was sent along with Clairaut, Maupertius, and Monier, to measure a degree of the meridian at the north polar circle. During this opera tion, which was completed in 1737, Camus rendered him self highly useful, not merely as an astronomer, but as a mechanician and an artist ; and to his address and genius the operation owed a great part of its success.
\\Then Mairan succeeded Fontenelle as secretary to the academy, Camas was appointed, on the 18th Janu ary 1741, to the situation of pensioner-geometrician held by that learned philosopher. In the same year, his at tention was directed to the subject of measuring the ca pacity of vessels for containing liquids ; and he invented a gauging-rod and for calculating the con tents of casks of every form. In 1746, Camus found a difference between the length of the standard cll, and that which was fixed by law ; and the academy being consulted on this subject, he was appointed, along with 1\i. }knot, to examine it. The cause of the diffcrencr was soon discovered, and likewise the reason why the ell vas not composed of any aliquot parts of the toise. In 1747, Camus published a memoir on the tangents of points common to several branches or the same curve ; and, a short time afterwards, he was appointed to the place of examiner of the schools of engineers and artil lery. In this new situation, his time was much occupied by travelling, but he still found leisure to compose a complete course of mathematics for the use of the engi neers, which appeared at different times, in 4 volumes Svo.
In 1756, Camus was one of the eight academicians who were appointed to examine, by a new measurement, the distance, between the centres of the pyramids of Villejuifve and Juvisi, which had formerly been mea sured by Picard ; and he has given a full account of this operation in the Memoirs of the Academy for 1754.
Camus married, in 1733, Mademoiselle Fournier, by whom he had four daughters, only one of whom arrived at maturity. This lady, whom her father loved with the most unusual tenderness, was married to M. Pagin, treasurer to the Count de Clermont. In the rigorous winter of 1766, Camus caught a severe cold in his breast during his travels to examine the schools of ar tillery; and his health had just been re-established by M. Petit, when the death of his only daughter, on the 4th December 1767, occasioned a relapse. After this distressing event, his health gradually declined, and he expired on the 4th of May 1768, in the 69th year of his age.
M. Camus was above the middle size, and was dis tinguished by the frankness of his manner, and by an unyielding integrity of character. He left behind him a great number of manuscripts, among which were, treatises on the various subjects of Dialling, Mechanics, the Differential and Integral Calculus, Algebra, Hy draulics, Conic Sections ; Perspective ; on the Division of Time, and the Machines which are employed to mea sure it; on the Toise ; on Vaults ; on Winches; on Practical Geometry ; on the application of Algebra to Geometry ; on the Mines of Sweden.
The following is a complete list of the writings of Cams: , 24 • V o_ •