Some time after this, the famous occu list Wenzel], by couching the cataract, restored our author to sight ; but the joy produced by this operation was of short duration. Some instances of negligence on the part of his surgeons, and his own impatience to use an organ, whose cure was not completely finished, deprived him a second time, and for ever, of his sight: a relapse which was also accom panied with tormenting pain. With the assistance of his sons, however, and of Messrs. Krafft and Lexell, he continued his labours : neither the infirmities of old age, nor the loss of his sight, could quell the ardour of his genius. Ile had engag ed to furnish the academy of Petersburgh with as many memoirs as would be suffi cient to complete its acts for twenty years after his death. In the space of seven years he transmitted to the academy above seventy memoirs, and above two hundred more, left behind him, were re vised and completed by a friend. Such of these memoirs as were of ancient date were separated from the rest, and form a collection that was published in the year 1783, under the title of " Analytical Works." The general knowledge of our author was more extensive than could well be expected in one who had pursued, with such unremitting ardour, mathematics and astronomy as his favourite studies. He had made a very considerable pro gress in medical, botanical, and chemical SCICIICC. What was still more extraordi nary, he was an excellent scholar, and possessed in a high degree what is gene rally called erudition. He had attentive ly read the most eminent writers of an cient Rome ; the civil and literary history of all ages and of all nations was familiar to him ; and foreigners, who were only acquainted with his works, were astonish ed to find, in the conversation of a man, whose long life seemed solely occupied in mathematical and physical researches and discoveries, such an extensive ac quaintance with most interesting branches of literature. In this respect,
no doubt, he was much indebted to a very uncommon memory, which seemed to re tain every idea that was conveyed to it, either from reading or from meditation. He would repeat the /Eneid of Virgil, from the beginning to the end, without hesitation, and indicate the first and last line of every page of the edition he used.
Several attacks of a vertigo, in the be ginning of September, 1783, which did not prevent his computing the motions of the aerostatic globes, were, however, the forerunners of his mild passage out of this life. While he was amusing himself at tea with one of his grand children, he was struck with an apoplexy, which ter minated his illustrious career at seventy six years of age.
M. Euler's constitution was uncommon ly strong and vigorous. His health was good, and the evening of his long'life was calm and serene, sweetened by the fame that follows genius, the public esteem and respect, that are never withheld from ex emplary virtue, and several domestic com forts, which he was capable of feeling, and therefore deserved to enjoy.
The catalogue of his works has been printed in fifty pages, fourteen of which contain the manuscript works. The print ed ones consist of works published sepa rately, and works to be found in the me moirs of several academies, viz. in thirty eight volumes of the Petersburgh acts, (from six to ten papers in each volume ;) in several volumes of the Paris acts ; in twenty-six volumes of the Berlin acts, (about five papers to each volume ;) in the Acta Eruditorum, in two volumes ; in the Miscellanea Taurinensia, in vol. ix. of the Society of Ulyssingue ; in the Ephe merides of Berlin; in the Memoires de la Soci4ti Oeconomique, for 1766.