ules for making discoveries, or methods of induction, have
never been consciously, nor often indeed unconsciously, followed by
discoverers. They are not in fact practical rules at all, though they
were so intended. His really strong doctrines are that phenomena must be
studied direct, and that variations in the ordinary course of nature
must be induced by aid of experiment; but he lacked the scientific
instinct for pursuing these great truths into detail and special cases.
He sneered at the work and methods of both Gilbert and Galileo, and
rejected the Copernican theory as absurd. His literary gifts have
conferred on him an artificially high scientific reputation, especially
in England; at the same time his writings undoubtedly helped to make
popular the idea of there being new methods for investigating Nature,
and, by insisting on the necessity for freedom from preconceived ideas
and opinions, they did much to release men from the bondage of
Aristotelian authority and scholastic tradition.

The greatest name between Galileo and Newton is that of Descartes.

_Rene Descartes_ was born at La Haye in Touraine, 1596, and died at
Stockholm in 1650. He did important work in mathematics, physics,
anatomy, and philosophy. Was greatest as a philosopher and
mathematician. At the age of twenty-one he served as a volunteer under
Prince Maurice of Nassau, but spent most of his later life in Holland.
His famous _Discourse on Method_ appeared at Leyden in 1637, and his
_Principia_ at Amsterdam in 1644; great pains being taken to avoid the
condemnation of the Church.

Descartes's main scientific achievement was the application of algebra
to geometry; his most famous speculation was the "theory of vortices,"
invented to account for the motion of planets. He also made many
discoveries in optics and physiology. His best known immediate pupils
were the Princess Elizabeth of Bohemia, and Christina, Queen of Sweden.

He founded a distinct school of thought (the Cartesian), and was the
precursor of the modern mathematical method of investigating science,
just as Galileo and Gilbert were the originators of the modern
experimental method.

LECTURE VI

DESCARTES AND HIS THEORY OF VORTICES

After the dramatic life we have been considering in the last two
lectures, it is well to have a breathing space, to look round on what
has been accomplished, and to review the state of scientific thought,
before proceeding to the next great era