CAMUS (CaAaLzs STZPHEN Louis), a mathe matician and mechanician : born at Creasy en Brie, near Meaux, the 25th August 1699 ; son of Stephen Camas, a surgeon of that town, and Margaret Mail lard.
His taste for practical mechanics was very early demonstrated by a singular ingenuity in the con struction of a variety of little machines, with which he amused himself; and he soon felt so strongly the value of mathematical studies, that he urged his pa rents to find the means of sending him to a school where he might apply to them. In compliance with his wishes, he was placed, when he was little more than ten years old, at the College de Navarre, in Paris : and in two years he acquired knowledge enough to become an instructor of others, and to re lieve his friends from all further expence in his edu cation. He was assisted, in the pursuit of the higher departments of the mathematics, by the celebrated M. Varignon.; and he particularly applied himself to civil and military architecture, and to astro nomy.
• 1. The first remit of his studies that was destined for the public eye, was an essay On the Masts of Ships, a subject which had been proposed in 1727 as a prize question by the Academy of Sciences. This essay was received with considerable appro bation, and was inserted in the second volume of the Collection e. Prize Memoirs : shortly after, the author was made an. Adjunct, or Subassoci ate, of the Academy, in the department of Mecha nics.
2. In 1728 he brought forwards a memoir on the Living force of bodies in motion, in which he con cludes, from considering the actions of springs, and ether similar powers, that its true measure is the product of the mass into the square of the velocity, as Leibnitz maintained : this product being also pro portional to that of the force into the space through which it acts, while the momentum is proportional to the force and the time conjointly. In December 1780, M. Camus was appointed Professor of Geo ' metry to the Academy of Architecture,' and a few years afterwards he became Secretary to the same body.
5. The Memoirs Ville Academy for 1792 containa short paper on a Problem proposed by M. Cramer, respecting the determination of two curves bearing a particular relation to each other. It was the cus tom of the age to consider exercises of this sort as trials of strength, to which it was incumbent on all geometricians to submit, for the honour of the coun tries in. which they lived, and of the societies to
which they belonged. The author was elevated in 1788 to the rank of an Associate of the Academy, together with Clairaut, over whom he even obtained some advantage in the ballot.
4. He communicated to the Academy, in the same year, a valuable paper on the Teeth of Wheels. La hire had already laid the foundation of the investiga. tion on its true basis, and had pointed out the use of different epicycloidal curves for the forms of the teeth of wheels in different circumstances : and M. Camus, in this essay, enters into some further in. etuiries, particularly with regard to the best propor tions for the length of the teeth, and the comparo tive diameters of the wheels : a discussion for which his intimate acquaintance with the art of the clock. maker made him particularly well qualified. In 1756 he accompanied Maupertuis and Clairaut in the expedition to Lapland, for the measurement of a de. gree of the meridian ; and he was enabled to render them very essential service, not only as a geome. trician and an astronomer, but also by his skill in various departments of the mechaniCal arts, which became particularly valuable in so remote a situation.
5. M. Camus directed his attention in 1738 to the well known but interesting mechanical phenomo non of a Pistol ball piercing an open door, without causing any very sensible motion in the door, and published a paper on the subject in the Memoir, of the Academy. He justly observes, that the effect of any force depends, not only on its magnitude, butt& so on the time for which it operates ; and that though the impulse of the ball must tend to carry the door before It, with a force paramount to the resistance which it opposes to the ball, yet the time of dip so tion of this force is too short to produce a sensible effect on the whole mass of the door. 6, 7. In 1739 he presented to the Academy two hydraulic me moire, the one on Water buckets, the other on Pumps. In the latter he investigates the diameter of a valve, capable of transmitting the greatest quantity of wo ter, within a given barrel ; a valve which is too large not being at liberty to rise to a sufficient height.