ss, and consequently its discharges greater in dry weather than in wet weather; which may be thus accounted for: the moisture of the air moistens the fibres of the skin and lessens perspiration by lessening their vibratory motion. When perspiration is thus lessened by the moisture of the air, urine indeed is by degrees increased, but not equally. Hence, according to Dr Bryan Robinson, we learn, that to keep a body of the same weight in wet weather as in dry, either the quantity of food must be lessened, or the proportion of the meat to the drink increased; and both these may be done by lessening the drink without making any change in the meat.

The instrument used for determining the degree of moisture in the air, is called an hygrometer. See Hygrometer.Abraham, a learned mathematician, was born at Vitri in Champagne, in France, 1667, where his father was a surgeon. At the revocation of the edict of Nantes, he came to England. Before he left France, he had begun the study of mathematics; and having perfected himself in that science in London, he was obliged, by necessity, to teach it. Newton's Principia, which accidentally fell into his hands, showed him how little progress he had made in a science of which he thought himself master. From this work he acquired a knowledge of the geometry of infinitesimals with as great facility as he had learned the elementary geometry; and in a short time he was fit to be ranked with the most celebrated mathematicians. His success in these studies procured him a seat in the Royal Society of London and in the Academy of Sciences at Paris. His merit was so well understood in the former, that he was thought capable of deciding in the famous dispute between Leibnitz and Newton concerning the differential calculus.—He published a Treatise on Chances in 1738, and another on Annuities in 1752; both extremely accurate. The Philosophical Transactions contain many interesting memoirs of his composition.—Some of them treat of the method of fluxions; others are on the lunula of Hippocrates; others on physical astronomy, in which he resolved many important problems; and others, in short, on the analysis of the games of chance, in which he followed a different course from that of Montmort. Towards the close of his life he lost his sight and hearing; and the demand for sleep became so great that he required 20 hours of it in a day. He died at London, 1754, aged 87. His knowledge was not confined to mathematics; but he retained to the last a taste for polite literature. He was intimately acquainted with the best authors of antiquity; and he was frequently consulted about difficult passages in their works. Rabelais and Molière were his favourite French authors: he had them by heart; and he once observed to one of his acquaintances, "that he would rather have been Molière than Newton." He recited whole scenes of the Misanthrope, with that delicacy and force with which he remembered to have heard them recited at Paris 70 years before, by Molière's own company. The character indeed was somewhat similar to his own. He judged severely of mankind; and could never conceal his disgust at the conversation of a fool, or his aversion to cunning and dissimulation. He was free from the affectation of science, and no one could know him to be a mathematician but from the accuracy of his thoughts. His conversation was general and instructive. Whatever he said was well digested and clearly expressed. His style possessed more strength and solidity than ornament and animation; but he was always correct, and he bestowed as much pains on his sentences as on his calculations. He could never endure any bold affections or indecent witticisms against religion.