e melancholy yellow
Of the Icelandic fields; and, wearying
Their lily wings amid the boreal lights,
Journey away unto the joyous shores
Of morning.

From 'An Hour of My Youth.'

JEAN LE ROND D'ALEMBERT

(1717-1783)

[Illustration: D'ALEMBERT]

Jean Le Rond D'Alembert, one of the most noted of the "Encyclopedists,"
a mathematician of the first order, and an eminent man of letters, was
born at Paris in 1717. The unacknowleged son of the Chevalier Destouches
and of Mme. de Tencin, he had been exposed on the steps of the chapel
St. Jean-le-Rond, near Notre-Dame. He was named after the place where he
was found; the surname of D'Alembert being added by himself in later
years. He was given into the care of the wife of a glazier, who brought
him up tenderly and whom he never ceased to venerate as his true mother.
His anonymous father, however, partly supported him by an annual income
of twelve hundred francs. He was educated at the college Mazarin, and
surprised his Jansenist teachers by his brilliance and precocity. They
believed him to be a second Pascal; and, doubtless to complete the
analogy, drew his attention away from his theological studies to
geometry. But they calculated without their host; for the young student
suddenly found out his genius, and mathematics and the exact sciences
henceforth became his absorbing interests. He studied successively law
and medicine, but finding no satisfaction in either of these
professions, with the true instincts of the scholar he chose poverty
with liberty to pursue the studies he loved. He astonished the
scientific world by his first published works, 'Memoir on the Integral
Calculus' (1739) and 'On the Refraction of Solid Bodies' (1741); and
while not yet twenty-four years old, the brilliant young mathematician
was made a member of the French Academy of Sciences. In 1754 he entered
the Academie Francaise, and eighteen years later became its perpetual
secretary.

D'Alembert wrote many and important works on physics and mathematics.
One of these, 'Memoir on the General Cause of Winds,' carried away a
prize from the Academy of Sciences of Berlin, in 1746, and its
dedication to Frederick II. of Prussia won him the friendship of that
monarch. But his claims to a place in French literature, leaving aside
his eulogies on members of the French Academy deceased between 1700 and
1772, are based chiefly on his writings in connection with the
'Encycloped