ney of to-day.

The payment received by Diderot is a little doubtful, and the terms were
evidently changed from time to time. His average salary, after
D'Alembert had quitted him, seems to have amounted to about three
thousand livres, or one hundred and thirty pounds sterling, per annum.
This coincides with Grimm's statement that the total sum received by
Diderot was sixty thousand livres, or about two thousand six hundred
pounds sterling.[157] And to think, cried Voltaire, when he heard of
Diderot's humble wage, that an army contractor makes twenty thousand
livres a day! Voltaire himself had made a profit of more than half a
million livres by a share in an army contract in the war of 1734, and
his yearly income derived from such gains and their prudent investment
was as high as seventy thousand livres, representing in value a sum not
far short of ten thousand pounds a year of our present money.

II.

All writers on the movement of illumination in France in the eighteenth
century, call our attention to the quick transformation, which took
place after the middle of the century, of a speculative or philosophical
agitation into a political or social one. Readers often find some
difficulty in understanding plainly how or why this metamorphosis was
brought about. The metaphysical question which men were then so fond of
discussing, whether matter can think, appears very far removed indeed
from the sphere of political conceptions. The psychological question
whether our ideas are innate, or are solely given to us by experience
through the sensations, may strike the publicist as having the least
possible to do with the type of a government or the aims of a community.
Yet it is really the conclusions to which men come in this region, that
determine the quality of the civil sentiment and the significance of
political organisation. The theological doctors who persecuted De Prades
for suggestions of Locke's psychology, and for high treason against
Cartesianism, were guided by a right instinct of self-preservation. De
Maistre, by far the most acute and penetrating of the Catholic school,
was never more clear-sighted than when he made a vigorous and deliberate
onslaught upon Bacon, the centre of his movement against revolutionary
principles.[158]

As we have said before, the immediate force of speculative literature
hangs on practical opportuneness. It was not merely because Bacon and
Hobbes and Locke had written certain books,