This distinguished mathematician, whose European fame is stated by Lord Brougham to have been, during his life, greater than that enjoyed by any other man of science in any age, was born in Paris on the 17th of November, 1737. Immediately on his unwelcome entrance into the world, which was ere long to be so proud of his genius, his existence was imperilled from his being abandoned by his mother to the cold air of a winter's night, near the Church of St. Jean le Rond. From this position he was fortunately rescued by the police, who, perceiving that the infant's life was in the utmost danger, delivered him into the care of a poor but respectable glazier's wife in the neighbourhood, who nursed him with peculiar tenderness. In a few days the father came forward to acknowledge the foundling, and made provision for his maintenance. The mother, who was afterwards celebrated for her wit and accomplishments in the fashionable circles of Paris, was in no haste to follow the example. Indeed she manifested not the slightest sign of desiring to make the acquaintance of her son, till he had acquired fame and distinction. Vanity then prompted her to seek that intimacy which the ordinary feelings of a parent had never induced her to desire. When that time arrived, however, and she requested him, in presence of his affectionate nurse, to come and live with her, he exclaimed, pointing to the latter,—

"Ma mere! ah! la voila! Je ne connais point d'autre;" and embraced the glazier's spouse with tears of filial and grateful affection.

At the age of twelve D'Alembert was sent to the College of the Quatre Nations, the professors of which belonged to the Jansenist party. Observing unmistakeable signs of early genius in the boy, they strove to implant in his young breast a love of polemical subjects.

"In the first year of his studies in philosophy," says Lord Brougham, "he had written an able and learned commentary of St. Paul's Epistle to the Romans; and as he showed a general capacity for science, the worthy enemies of the Jesuits, delighted to find that all profound learning was not engrossed by that body, cherished a hope that a new Pascal had been given to them for renewing their victories over their learned and subtle adversaries."

It proved vain, however; for his "History of the Destruction of the Jesuits," published long after, is rather laudatory of the genius and accomplishments of that body; and his literary productions are pronounced to be quite unequal in merit to those on scientific subjects. But it was with this view that D'Alembert's attention was directed to those figures and calculations of which he forthwith became so enamoured, and in regard to which he subsequently distinguished himself so conspicuously among his contemporaries.

On leaving college he returned to the humble dwelling that had sheltered his infancy, considerately thinking that the small income he derived from his father would minister to the comforts of those who had guarded and watched over him in childhood. There, in a small apartment that served both for study and bedroom, he continued to reside for forty years, at the end of which his health obliged him to remove to a more airy abode.

In this obscure retreat he applied himself with heart and soul to his favourite study. In prosecuting it he often, like Ferguson the astronomer, made what he believed to be original discoveries, till awakened from the pleasing delusion by some treatise, which he had not previously had the advantage of consulting Such books, indeed, as his means permitted him to purchase he made himself master of; but the greater number he was obliged to read at the public libraries to which he had access.

Devoted as he was to Geometry, the very mo derate amount of his income still rendered it advisable that he should qualify for some profession likely to yield him a competence, and he accord ingly tried law; but, finding it quite foreign to his tastes, he turned to medicine. In this he was equally unsuccessful; for though, in order that he might not be tempted from it, he sent his mathematical books to a friend's house till he should have taken his degree, his heart, untravelled, still remained with his favourite study; he received back one volume after another till he had re possessed himself of the whole; and, like the great Galileo, finding his medical schemes impracticable, he abandoned a hopeless struggle, and allowed his inclination to take its natural course.

His investigations were fruitful of the most pleasant and serene enjoyment to himself, notwithstanding that his kind foster-mother would often say, "Oh, you will be nothing better than a philosopher—a foolish man who wears his life out to be talked of after he's dead."

But, luckily, she proved no prophetess; for his studies ere long brought him into that notice which might have been anticipated from the enthusiastic diligence with which they had been followed. An important paper, presented to the Academy of Sciences, impressed that learned body so favourably with his capacity and talents, that he became one of its members, at the almost unprecedentedly early age of twenty-two.

Two years later, his "Traite de Dynamique' raised him to the highest rank of geometricians. In 1746 he produced his "Memoir on the Theory of Winds," and afterwards his "Essai sur la Re-sistance des Fluides." He was joint-editor with Diderot of the "French Cyclopedia," commenced in 1751, to which he contributed many of the best articles, especially on mathematical subjects

The controversies in which his literary productions involved him were so unsuited to his tastes and habits, that he always returned with renewed zeal and heartfelt satisfaction to the cultivation of science.

Having declined a handsome invitation of the King of Prussia to settle at Berlin, he was, in 1772, chosen Secretary to the Academy of Sciences.

He died on the 29th of April, 1783.