8. He inserted in the Memoirs for 1740 a confu tation of a Mechanical fallacy, which ban misled many of the enthusiasts who have bewildered them selves in 'the search of a perpetual motion : demon strating, that when a number of weights are caused to descend, in any imaginable paths, at a greater distance from the centre of a wheel than they ascend, the number of the weights descending at any one time must • always be smaller than those of the weights ascending ; and in such a proportion, as per fectly to compensate for the mechanical advantage apparently gained by the greater distance. In the following year he was received into the number of the Academicians, in the department of Geometry, on occasion of tbe resignation of M. Fontenelle. 9. He published also, in the Memoirs for 1741, an account of a Gauging rule, for measuring barrels of different forms, by simple inspection of the lord' mic scales engraved on it, observing only some easy rules for their adjustment, according to the general nature of the solid. 10. In 1746 he presented Report, in conjunction with M. Hellot, on the Lesgtll of the Standard Ell, which was thought worthy Of being inserted in the collection of the Academy 5 .
11. We find among the Memoirs for 1747 an may of M. Cams on the Tangents of Curves having se. veral branches, crossing each other ; which ffequent. ly require, for their determination, the use of fiuxions of the higher orders, the first fiuxions of the abscise and ordinate vanishing together. M. Saurin had before giien a similar solution of the problem, but had not attempted to explain the metaphysical ground, upon which the apparent paradox is recon ciled to the general principles of the differential me thod.
12. M. Cantu also assisted in several determina tions and reports which were referred at various times to committees of the Academy ; and particularly in the remeasurement of M. Picard's base from Vile
juif to Juvisy, which was performed by eight mem bers, and recorded in the Memoirs for 1754.
13. The latter years of his life were much occu pied in various engagements connected with the of fices of Examiner in the schools of the Royal Engi neers and in that of the Artillery, to which he was nominated by the King. He undertook, for the ad vantage of the students in these schools, the labo rious task of reducing into a uniform system a com plete course of mathematical study, in which the geometrical method was as much as possible observ ed; and which is considered as highly creditable to his talents and exertions : it was entitled Cours des Mathentatigues, 4 vols. 8vo. 14. He also published an Elementary work on Arithmetic.
In person M. Camas was tall ; his countenance was agreeable ; his manners firm, and occasionally somewhat warm ; but he was far from being either morose or vindictive. He wag elected a foreign member of the Royal Society of London in January 1764. He married, in 1733, Made. M. A. M. Four rier, and had four daughters, the eldest of whom was married to M. Pagin ; the others died young. His last illness was supposed to have originated from a cold, taken in a professional journey, during the .hard winter of 1766; and to have been aggravated by affliction for the loss of his surviving daughter: he died a few months after her, on the 4th May 1768. He left a variety of manuscripts, demonstrative of his habitual diligence, and of the extent of his re searches ; but not deemed of sufficient importance to meet the hazards of posthumous publication. (Hist. Aced. Par. 1768. P. 144.) z.)