EUI.ER (LxoNAttn,) in biography, one of the most extraordinary, and even prodigious, mathematical geniuses that the world ever produced. He was a na tive of Basil, and was born April 15, 1707. The years of his infancy were passed at Richen, where his father was minister. He was afterwards sent to the university of Basil ; and as his memory was prodigious and his application regu lar, he performed his academical tasks with great rapidity ; and all the time that he saved by this was consecrated to the study of mathematics, which soon became his favourite science. The early pro gress he made in this study added fresh ardour to his application, by which, too, he obtained a distinguished place in the attention and esteem of Professor John Bernoulli, who was then one of the chief mathematicians in Europe.
In 1723, M. Euler took his degree as master of arts, and delivered on that oc casion a Latin discourse, in which he drew a comparison between the philoso phy of Newton and the Cartesian system, which was received with the greatest ap plause. At his father's desire he next applied himself to the study of theology and the oriental languages ; and though these studies were foreign to his predo minant propensity, his success was con siderable even in this line. However, with his father's consent, he afterwards returned to mathematics as his principal object. In continuing to avail himself of the councils and instructions of M. Ber noulli, he contracted an intimate friend ship with his two sons, Nicholas and Daniel; and it was chiefly in consequence of these connections, that he afterwards became the principal ornament of the phi. losophical world.
The project of erecting an academy at Petersburgh, which had been formed by Peter the Great, was executed by Ca tharine the First : and the two young Bernoullis being invited to Petersburgh in 1725, promised Euler, who was desir ous of following them, that they would use their endeavours to procure for him an advantageous settlement in that city. In the mean time, by their advice, he made close application to the study of philosophy, to which he made happy applications of his maths matical know e, in a dissertation on the nature and propagation of sound, and an answer to a prize question concerning the roasting of ships ; to which the Academy of Sci ences adjudged the accessit, or second rank, in the year 1727. From this latter
discourse, and other circumstances, it ap pears that Euler had very early embark ed in the curious and useful study of naval architecture, which he afterwards enrich ed with so many valuable discoveries. The study of mathematics and philoso phy, however, did not solely engage his attention, as he, in the mean time, attend ed the medical and botanical lectures of the professors at Basil.
Euler's merit would have given him an easy admission to honourable preferment, either in the magistracy or university of his native city, if both civil and cal honours had not been there distribut ed by lot. The lot being against him in a certain promotion, he left his country, set out for Petersburgh, and was made joint professor with his countrymen, Herman and Daniel Bernoulli, in the university of that city.
At his first setting out in his new ca reer, he enriched the academical collec tion with many memoirs, which excited a noble emulation between him and the Bernoullis ; an emulation that always continued, without either degenerating into a selfish jealousy, or producing the least alteration in their friendship. It was at this time that he carried to new de , grecs of perfection the integral calculus, invented the calculation by sines, reduced analytical operations to a greater simpli city, and thus was enabled to throw new light on all the parts of mathematical science.
In 1730 M. Euler was promoted to the professorship of natural philosophy ; and in 1733 he succeeded his friend D. Ber noulli in the mathematical chair. In 1735, a problem was proposed by the .Academy,which required expedition, and for the calculation of which some eminent mathematicians had demanded the space of some months. The problem was un dertaken by Euler, who completed the f•alculation in three days, to the astonish Ment of the Academy : but the violent and laborious efforts it cost him threw him into a fever, which endangered his life, and deprived him of the use of his right eye, which afterwards brought.on a total blindness.