EULER, LEONARD, a celebrated mathematician of the last century, was born on the 15th of April 1707, at Basel, in Switzerland ; his father, Paul Euler, was the Calvinistic pastor of the neighbouring village of Riechen. He was a man remarkable for unostentatious piety, and imbued with a considerable knowledge of mathematics, which he had acquired under the tuition of James Bernoulli.
After being instructed by his father in analytical science, young Euler was sent to the university of Basel, in which John Bernoulli was at that time professor, and by his rapid progress and decided mathematical genius he so far gained the esteem of his teacher and of the sons, Nicholas and Daniel Bernoulli, that his father was easily dissuaded from his original intention of forming his son into a divine, and wisely allowed him to pursue unshackled the high distinctions then conferred by a profound scientific reputation.
A prize having been proposed by the French Academy of Sciences on the management of vessels at sea, the ambition of Euler, then only nineteen years of age, induced him to attempt an essay, which was received with considerable applause, though the prize was con ferred ou Bouguer, an old and experienced professor of hydrography.
The Academy of Sciences at St. Petersburg was then rising to a distinguished rank amongst similar institutions in Europe under the fostering patronage of Catharine I., who had invited several philo sophers to her capital, among whom were the Bernoullis above mentioned. On the retirement of Daniel Bernoulli, Euler was appointed professor of mathematics under Peter I. in 1733; soon after which be married a Swiss lady named Gsell, by whom he had a numerous family.
His works previous to tho date at which we have arrived were, with few exceptions, confined to those mathematical questions arising from the progressive march of the Integral Calculus, which, at that time, caused much emulation in different countries. In general, Euler was far more in his element in the abstruser parts of pure mathematics than in the applied ; in many of the latter he was frequently conducted to paradoxical results.
In the memoirs of the Petropulitan Academy, 1729 and 1732, are found several of his memoirs on trajectories, tautochrouous curves, the shortest line along a surface between two given poiuts,•and on differential equations ; besides which he had published at Basel a physical dissertation on sound.
Euler found it convenient at this time to apply himself intensely to study, not more from his natural ardour for the sciences and the incentive of an increasing reputation thau from the desire to avoid the political intrigues which, under a suspicious and tyrannical minister, then agitated Russia.
During this interval he published an excellent treatise on mechanics (Petersburg, 1736, 2 vole., 4to), a treatise on the theory of music, and one on arithmetic, together with numerous papers in the Petersburg Memoirs, chiefly on astronomical and purely mathematical subjects, among which are contained his views on the solution of Iaoperis metrical Problems, which embodied the profoundest researches on a matter of great analytical difficulty previous to the discovery of the Calculus of Variations by Lagrange. Upon the fall of Biren he gladly accepted an invitation from the King of Prussia to visit Berlin. When he was introduced to the queen•dowager in 1741, she was so much struck with the paucity of his conversation that on requiring an explanation, he replied that he had just returned from a country where those who spoke were hanged.
The princess of Anhalt-Dessau, being desirous to profit by the presence of Euler in Berlin, requested to be favoured with instructions on the known facts in the physical sciences. To this wish he fully acceded on his return to St. Petersburg in 1766, by publishing his celebrated work, Letters to a German Princess' (3 vole., 8vp, 1768); in which he discusses with clearness the most important truths in mechauics, optics, sound, and physical astronomy, having published previous to this date several isolated treatises and some hundred memoirs touching ou every known branch of theoretical and practical mathematics. During his residence in Prussia he was much employed by the enlightened monarch who Shen governed that kingdom in questions connected with the mint, with navigable canals, &c. In the midst of such varied employments he was not forgetful of the ties which bound him to his native home; having learned his father's death, he went in 1750 to Frankfurt to receive his widowed mother, and brought her to Berlin, where sho lived until 1761, enjoying with a mother's feeling the glorious distinction to which her sou by his talents and indefatigable industry had arrived.