EULER. 



I 



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 

 phi'osophy, to which he made happy 

 applications of his mathi matical know- 

 led e, in a dissertation on the nature and 

 propagation of sound, and an answer to 

 a prize question concerning the masting 

 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 .hat 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 academi- 

 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 Petersburg!!, 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- 

 grees 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 

 calculation 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. 



The Academy of Sciences at Paris, 

 which in 1738 had adjudged the prize to 

 his memoir concerning the Nature and 

 Properties of Fire, proposed for the year 

 1740, the important subject of the tides 

 of the sea; a problem whose solution 

 comprehended the theory of the solar 

 system, and required the most arduous 

 calculations. Euler's solution of this 

 question was adjudged a masterpiece of 

 analysis and geometry; and it was more 

 honourable for him to share the academi- 

 cal prize with such illustrious competitors 

 as Colin Maclaurin and Daniel Bernoulli, 

 thwn to have carried it away from ri- 

 vals of less magnitude. Seldom, if ever, 

 did such a brilliant competition adorn 

 the annals of the Academy; and per- 

 haps no subject, proposed by that learn- 

 ed body, was ever treated with such force 

 of genius and accuracy of investigation, 

 as that which here displayed the philoso- 

 phical powers of that extraordinary tri- 

 umvirate. 



In the year 1741, M. Euler was invited 

 to Berlin, to direct and assist the Acade- 

 my that was there rising into fame. On 

 this occasion he enriched the last volume 

 of the Miscellanies (Melanges) of Berlin 

 with five memoirs, which form an emi- 

 nent, perhaps the principal figure in that 

 collection. These were followed, with 

 amazing rapidity, by a great number of 

 important researches, which are dispers- 

 ed through the memoirs of the Prussian 

 Academy : a volume of which has been 

 regularly published every year since its 

 establishment in 1744. The labours of 

 Euler will appear more especially asto- 

 nishing, when it is considered, that, while 

 he was enriching the Academy of Berlin 

 with a profusion of memoirs on the deep- 

 est parts of mathematical science, con- 

 taining always some new points of view, 

 often sublime truths, and sometimes dis- 

 coveries of great importance, he still 

 continued his philosophical contributions 

 to the Petersburgh Academy, whose me- 

 moirs display the surprising fecundity of 

 his genius, and which granted him a pen- 

 sion in 1742. 



It was with great difficulty that this 

 extraordinary man, 1766, obtained per- 

 mission from the King of Prussia to re- 

 turn to Petersburgh, where he wished to 

 pass the remainder of his days. Soon 



