Elements of Algebra

EULER. xi the energies of Euler's mind give way, even when the organs of the body were overpowered: for in the year 1735, having completed, in three days, certain astronomical calculations, which the academy called for in haste; but which several mathematicians of eminence had declared could not be performed within a shorter period than some months, the intense application threw him into a fever, in which he lost the sight of one eye. Shortly after his return to Petersburg, in 1766, he became totally blind. His passion for science, however, suffered no decline; the powers of his mind were not impaired, and he continued as indefatigable as ever. Though the distresses of age likewise were now crowding fast upon him, for he had passed his sixtieth year; yet it was in this latter period of his life, under infirmity, bodily pain, and loss of sight, that he produced some of his most valuable works; such as command our astonishment, independently of the situation of the author, from the labor and originality which they display. In fact, his habits of study and composition, his inventions and discoveries, closed only with his life. The very day on which he died, he had been engaged in calculating the orbit of Herschel's planet, and the motions of aërostatic machines. His death happened suddenly in September 1783, from a fit of apoplexy, when he was in the seventy-sixth year of his age. Such is the short history of this illustrious man. The incidents of his life, like that of most other