EINSTEIN AND SPECIFIC HEATS 399
which he acknowledged the quantum theory in his publications. His newly
aroused interest in the quantum theory was, however, thoroughly pragmatic. In
an address (on the occasion of the birthday of the emperor), he said:
At this time, the quantum theory is essentially a computational rule, one may
well say a rule with most curious, indeed grotesque, properties. However,...
it has borne such rich fruits in the hands of Planck and Einstein that there is
now a scientific obligation to take a stand in its regard and to subject it to
experimental test.
He went on to compare Planck with Dalton and Newton [N6]. Also in 1911,
Nernst tried his hand at a needed modification of Einstein's Eq. 20.4 [N7].
Nernst was a man of parts, a gifted scientist, a man with a sense for practical
applications, a stimulating influence on his students, and an able organizer. Many
people disliked him. But he commanded respect 'so long as his egocentric weakness
did not enter the picture' [E10]. He now saw the need for a conference on the
highest level to deal with the quantum problems. His combined talents as well as
his business relations enabled him to realize this plan. He found the industrialist
Ernest Solvay willing to underwrite the conference. He planned the scientific pro-
gram in consultation with Planck and Lorentz. On October 29, 1911, the first
Solvay Conference convened. Einstein was given the honor of being the final
speaker. The title of his talk: 'The Current Status of the Specific Heat Problem.'
He gave a beautiful review of this subject—and used the occasion to express his
opinion on the quantum theory of electromagnetic radiation as well. His contri-
butions to the latter topic are no doubt more profound than his work on specific
heats. Yet his work on the quantum theory of solids had a far greater immediate
impact and considerably enlarged the audience of those willing to take quantum
physics seriously.
Throughout the period discussed in the foregoing, the third law was applied
only to solids and liquids. Only in 1914 did Nernst dare to extend his theorem to
hold for gases as well. Eucken's results on the specific heat of molecular hydrogen
were a main motivation for taking this bold step [N8]. Unlike the case for solids,
Nernst could not point to a convincing theoretical model of a gas with the property
cv —> 0 as T -* 0. So it was to remain until 1925, when the first model of this
kind was found. Its discoverer: Einstein (Section 23b).
Einstein realized, of course, that his work on the specific heats of solids was a
step in the right direction. Perhaps that pleased him. It certainly puzzled him. In
1912 he wrote the following to a friend about his work on the specific heat of gases
at low temperatures:
In recent days, I formulated a theory on this subject. Theory is too presump-
tuous a word—it is only a groping without correct foundation. The more suc-
cess the quantum theory has, the sillier it looks. How nonphysicists would scoff
if they were able to follow the odd course of developments! [Ell]