l men were busy in trying to set each
other right, and in disputing and arguing with those who believed
themselves to be right. It was an era of intellectual pugilism,
and nothing was done in physics. In fact, this frame of mind is
incompatible with any marked success in scientific work.

The physical investigator cannot take up his work in the spirit of
controversy; for the phenomena and laws of Nature will not argue with
him. He must come as a learner, and the true man of science is content
to learn, is content to lay his results before his fellows, and is
willing to profit by their criticisms. In so far as he permits himself
to assume the mental attitude of one who defends a position, in so far
does he reveal a grave disqualification for the most useful scientific
work. Scientific truth needs no man's defense, but our individual
statements of what we believe to be truth frequently need criticism.
It is hardly necessary to remark, also, that critics are of various
degrees of excellence, and it seems that those in whom the habit of
criticism has become chronic are of comparatively little service to
the world.

The great harbinger of the new era was Galileo. There had been
prophets before him, and after him came a greater one--Newton. They
did nothing of note in electricity and magnetism, but they were filled
with the true spirit of science, they introduced proper and reasonable
methods of investigation, and by their great ability and distinguished
success they have produced a revolution in the intellectual world.
Other great men had also appeared, such as Leibnitz and Huyghens; and
it became very clear that the methods of investigation which had borne
such fruit in the days of Galileo were not disposed of completely
by his unwilling recantation; it became very clear that the new
civilization which was dawning upon Europe was not destined to the
rude fate which had overwhelmed the brilliant scientific achievements
of the Spanish Moors of a half century before.

Already in 1580, about the time when Galileo entered Pisa as a
student, Borroughs had determined the variation of the magnetic needle
at London, and we have upon the screen a view of his instrument, which
seems rude enough, in comparison with the elaborate apparatus of our
times. The first great work on electricity and magnetism was the "De
Magnete" of Gilbert, physician of Queen Elizabeth, published in
1600. Galileo, already famous in Europe, recognized in th