new geometric school sprang into existence in France before the close of this period. Lagrange would not permit a single diagram to appear in his Mécanique analytique, but thirteen years before his death, Monge published his epoch-making Géometrie descriptive.
Leonhard Euler (1707–1783) was born in Basel. His father, a minister, gave him his first instruction in mathematics and then sent him to the University of Basel, where he became a favourite pupil of John Bernoulli. In his nineteenth year he composed a dissertation on the masting of ships, which received the second prize from the French Academy of Sciences. When John Bernoulli's two sons, Daniel and Nicolaus, went to Russia, they induced Catharine I., in 1727, to invite their friend Euler to St. Petersburg, where Daniel, in 1733, was assigned to the chair of mathematics. In 1735 the solving of an astronomical problem, proposed by the Academy, for which several eminent mathematicians had demanded some months' time, was achieved in three days by Euler with aid of improved methods of his own. But the effort threw him into a fever and deprived him of the use of his right eye. With still superior methods this same problem was solved later by the illustrious Gauss in one hour![47] The despotism of Anne I. caused the gentle Euler to shrink from public affairs and to devote all his time to science. After his call to Berlin by Frederick the Great in 1747, the queen of Prussia, who received him kindly, wondered how so distinguished a scholar should be so timid and reticent. Euler naïvely replied, "Madam, it is because I come from a country where, when one speaks, one is hanged." In 1766 he with difficulty obtained permission to depart from Berlin to accept a call by Catharine II. to St. Petersburg. Soon after his return to Russia he became blind, but this did not stop his wonderful literary productiveness, which continued for seventeen years, until the
