had handed the business over to
Grimm, and by him it was continued until 1790, twelve years beyond the
life of Voltaire and of Rousseau, and six years after the death of the
ablest, most original, and most ungrudging of all those who gave him
their help.

An interesting episode in Diderot's life brought him into direct
relations with one of the two crowned patrons of the revolutionary
literature, who were philosophers in profession and the most arbitrary
of despots in their practice. Frederick the Great, whose literary taste
was wholly in the vein of the conventional French classic, was never
much interested by Diderot's writing, and felt little curiosity about
him. Catherine of Russia was sufficiently an admirer of the Encyclopaedia
to be willing to serve its much-enduring builder. In 1765, when the
enterprise was in full course, Diderot was moved by a provident anxiety
about the future of his daughter. He had no dower for her in case a
suitor should present himself, and he had but a scanty substance to
leave her in case of his own death. The income of the property which he
inherited from his father was regularly handed to his wife for the
maintenance of the household. His own earnings, as we have seen, were of
no considerable amount. There are men of letters, he wrote in 1767, to
whom their industry has brought as much as twenty, thirty, eighty, or
even a hundred thousand francs. As for himself, he thought that perhaps
the fruit of his literary occupations would come to about forty thousand
crowns, or some five thousand pounds sterling. "One could not amass
wealth," he said pensively, and his words are of grievous generality for
the literary tribe, "but one could acquire ease and comfort, if only
these sums were not spread over so many years, did not vanish away as
they were gathered in, and had not all been scattered and spent by the
time that years had multiplied, wants, grown more numerous, eyes grown
dim, and mind become blunted and worn."[239] This was his own case. His
earnings were never thriftily husbanded. Diderot could not deny himself
a book or an engraving that struck his fancy, though he was quite
willing to make a present of it to any appreciative admirer the day
after he had bought it. He was extravagant in hiring a hackney-coach
where another person would have gone on foot, and not seldom the
coachman stood for half a day at the door, while the heedless passenger
was expatiating within upon truth, virt