Calle, John Francis

, a French mathematician, was born on the 25th of October 1744, at Versailles, where he received a good education, and acquired an early taste for the mathematics. In 1768 he came to Paris, where he had an opportunity of being more thoroughly instructed. In 1774 he formed some distinguished pupils for the school of engineers, where the examinations were strict, and admission difficult to be obtained. In 1779 he gained the prize proposed by the society of arts at Geneva, for escapements. In 1783 he completed his edition of “Gardiner’s Tables of Logarithms,” which were exceedingly convenient, of great utility, and very correct; and which possessed advantages above all the others. In 1788 he was appointed professor of hydrography at Vann.es, afterwards at Dunkirk; and in 1792 he | returned to Paris, and was for a few years professor des ingenieurs geographes at the depot of war. This place having been suppressed, he continued to teach in Paris, where he was always considered as one of the best mathematical masters lo whom pupils could apply. In 1795 he published the new stereotype edition of the “Tables of Logarithms,” considerably enlarged with logarithmic tables of the sines, according to the new decimal division of the circle. These are the first which ever appeared. Towards the end of 3797 he presented to the National Institute the plan of a new telegraph and a telegraphic language, accompanied with a dictionary of 12,000 French words adapted to it by A combination worthy of so able a mathematician. These labours had injured his health, and he had been a long time asthmatic, but, notwithstanding his condition, he published that year an excellent memoir on finding the longitude at sea, under the modest title of “A Supplement to the Trigonometry and Navigation of Bezout.” He died on the 14th of November, 1798, leaving behind him a daughter, born at Vannes in 1793. According to a tradition in the family, he was descended from Descartes. ¹