dominating principle, without a master and without a God."[21] Grétry,
the musical composer, declares that Diderot was one of the rare men who
had the art of blowing the spark of genius into flame; the first
impulses stirred by his glowing imagination were of inspiration
divine.[22]

Marmontel warns us that he who only knows Diderot in his writings, does
not know him at all. We should have listened to his persuasive
eloquence, and seen his face aglow with the fire of enthusiasm. It was
when he grew animated in talk, and let all the abundance of his ideas
flow freely from the source, that he became truly ravishing. In his
writings, says Marmontel with obvious truth, he never had the art of
forming a whole, and this was because that first process of arranging
everything in its place was too slow and too tiresome for him. The want
of ensemble vanished in the free and varied course of conversation.[23]

We have to remember then that Diderot was in this respect of the
Socratic type, though he was unlike Socrates, in being the disseminator
of positive and constructive ideas. His personality exerted a decisive
force and influence. In reading the testimony of his friends, we think
of the young Aristides saying to Socrates: "I always made progress
whenever I was in your neighbourhood, even if I were only in the same
house, without being in the same room; but my advancement was greater if
I were in the same room with you, and greater still if I could keep my
eyes fixed upon you."[24] It has been well said that Diderot, like
Socrates, had about him a something dæmonic. He was possessed, and so
had the first secret of possessing others. But then to reach excellence
in literature, one must also have self-possession; a double current of
impulse and deliberation; a free stream of ideas spontaneously obeying a
sense or order, harmony, and form. Eloquence in the informal discourse