entirely differently when we estimate the energies with reference
to different origins.

"It does not seem to me that your ideas fit in with what we know
about nature. If you ask my advice, I should not advise you to try
to publish them.

"At best you would be entering into a discussion (perhaps not in
bad company) in which words would play a greater part than precise
ideas.

"This is the way I feel about it.

"I remain,
"Yours faithfully,
"J.W. GIBBS."

Professor Gibbs's criticism of the illustration of water-mixture is
evidently just. Another might well have been used where the things mixed
are not material--for instance, the value of money deposited in a bank. If
A and B each deposits $100 to C's credit and C then draws $10, there is
evidently no way of determining what part of it came from A and what from
B. The structure of "value", in other words, is perfectly continuous.
Professor Gibbs's objections to an "atomic" theory of the structure of
energy are most interesting. The difficulties that it involves are not
overstated. In 1897 they made it unnecessary, but since that time
considerations have been brought forward, and generally recognized, which
may make it necessary to brave those difficulties.

Planck's theory was suggested by the apparent necessity of modifying the