e
introduction of the undulatory theory has a more pleasant side. Three
men, great both in character and in intellect, were concerned in
pressing its claims--Young, Fresnel, and Arago--and the relations of
these men form a picture unmarred by any of those petty jealousies that
so often dim the lustre of great names. Fresnel freely acknowledged
Young's priority so soon as his attention was called to it; and Young
applauded the work of the Frenchman, and aided with his counsel in the
application of the undulatory theory to the problems of polarization of
light, which still demanded explanation, and which Fresnel's fertility
of experimental resource and profundity of mathematical insight sufficed
in the end to conquer.

After Fresnel's admission to the Institute in 1823 the opposition
weakened, and gradually the philosophers came to realize the merits of
a theory which Young had vainly called to their attention a full
quarter-century before. Now, thanks largely to Arago, both Young and
Fresnel received their full meed of appreciation. Fresnel was given the
Rumford medal of the Royal Society of England in 1825, and chosen one of
the foreign members of the society two years later, while Young in turn
was elected one of the eight foreign members of the French Academy. As
a fitting culmination of the chapter of felicities between the three
friends, it fell to the lot of Young, as Foreign Secretary of the
Royal Society, to notify Fresnel of the honors shown him by England's
representative body of scientists; while Arago, as Perpetual Secretary
of the French Institute, conveyed to Young in the same year the
notification that he had been similarly honored by the savants of
France.

A few months later Fresnel was dead, and Young survived him only two
years. Both died prematurely, but their great work was done, and
the world will remember always and link together these two names in
connection with a theory which in its implications and importance ranks
little below the theory of universal gravitation.

VII. THE MODERN DEVELOPMENT OF ELECTRICITY AND MAGNETISM

GALVANI AND VOLTA

The full importance of Young's studies of light might perhaps have
gained earlier recognition had it not chanced that, at the time when
they were made, the attention of the philosophic world was turned with
the fixity and fascination of a hypnotic stare upon another field, which
for a time brooked no rival. How could the old, familiar phenomenon,