d twenty, in the Dutch army, he marched over
Germany in the service of several princes, returned to France, where he
sold his property, travelled through the whole of Italy, and ended, in
1629, by settling himself in Holland, seeking everywhere solitude and
room for his thoughts. "In this great city of Amsterdam, where I am
now," he wrote to Balzac, "and where there is not a soul, except myself,
that does not follow some commercial pursuit, everybody is so attentive
to his gains, that I might live there all my life without being noticed
by anybody. I go walking every day amidst the confusion of a
great people with as much freedom and quiet as you could do in your
forest-alleys, and I pay no more attention to the people who pass before
my eyes than I should do to the trees that are in your forests and to the
animals that feed there. Even the noise of traffic does not interrupt my
reveries any more than would that of some rivulet." Having devoted
himself for a long time past to the study of geometry and astronomy, he
composed in Holland his Treatise on the World (_Traite du Monde_). "I
had intended to send you my _World_ for your New Year's gift," he wrote
to the learned Minime, Father Mersenne, who was his best friend; "but I
must tell you that, having had inquiries made, lately, at Leyden and at
Amsterdam, whether Galileo's system of the world was to be obtained
there, word was sent me that all the copies of it had been burned at
Rome, and the author condemned to some fine, which astounded me so
mightily that I almost resolved to burn all my papers, or at least not
let them be seen by anybody. I confess that if the notion of the earth's
motion is false, all the foundations of my philosophy are too, since it
is clearly demonstrated by them. It is so connected with all parts of my
treatise that I could not detach it without rendering the remainder
wholly defective. But as I would not, for anything in the world, that
there should proceed from me a discourse in which there was to be found
the least word which might be disapproved of by the church, so would I
rather suppress it altogether than let it appear mutilated."

Descartes' independence of thought did not tend to revolt, as he had
proved: in publishing his _Discourse on Method_ he halted at the
threshold of Christianism without laying his hand upon the sanctuary.
Making a clean sweep of all he had learned, and tearing himself free,
by a supreme effort, from the