Fate wanted d’Alembert, the great mathematician, not some prosperous, unproductive mediocrity of a Paris apothecary. The crowning blessing of life, to be born with a bias to some pursuit, was this man’s to the full. He yielded to Nature and to God. He brought back the books he had abandoned, flung aside those for which he had neither taste nor aptitude, and at twenty gave himself to the work for which he had been created. Some artist should put on canvas the picture of this student, sitting in his ill-aired garret with its narrow prospect of ‘three ells of sky,’ poor, delicate, obscure--or rich, rather, in the purest of earthly enjoyments, the pursuit of truth for its own sake. He could not afford to buy many of the books he needed, so he borrowed them from public libraries. He left the work of the day anticipating with joy the work of the morrow. For the world he cared nothing, and of him it knew nothing. Fame?--he did not want it. Wealth?--he could do without it. Poor as he was, there was no time when he even thought of taking pupils, or using the leisure he needed for study in making money by a professorship. To give knowledge was his work and his aim; to make knowledge easier for others he left to some lesser man. His style had seldom the grace and clearness which can make, and which in many of his fellow-workers did make, the abstrusest reasoning charm like romance. D’Alembert left Diderot to put his thought into irresistible words, and Voltaire and Turgot to translate it into immortal deeds. When he was two-and-twenty, in 1739, d’Alembert began his connection with the Academy of Sciences. In 1743 he published his ‘Treatise on Dynamics.’ Now little read and long superseded, it placed him at one bound, and at six-and-twenty years old, among the first geometricians of Europe. Modest, frugal, retiring as he was and remained, he was no more only the loving and patient disciple of science. He was its master and teacher. In 1746 his ‘Treatise on the Theory of Winds’ gained him a prize in the Academy of Berlin, and first brought him into relationship with Frederick the Great. Two years later, when her son was of daily growing renown, Madame de Tencin died. The story that, when he had become famous and she would fain have acknowledged him, he had repudiated her, saying he had no mother but the glazier’s wife, d’Alembert, declares Madame Suard, always denied. ‘I should never have refused her endearments--it would have been too sweet to me to recover her.’ That answer is more in keeping with a temperament but too gentle and forgiving, than the spirited repulse. It was in keeping also with the life of Madame de Tencin that even death should leave her indifferent to her child. She thought no more of him, he said, in the one than in the other. Her money she left to her doctor. If the studious poverty of the life in the glazier’s attic spared d’Alembert acquaintances, it did not deprive him of friends.