The Principles of Thermodynamics

2

First Law—The E = Mc

2

of

Thermodynamics

There is a tendency, particularly among physicists, to view the first law of thermody-

namics as merely a consequence of the energy conservation principle of mechanics.

That is to some extent a valid perspective today, when atomism has been firmly es-

tablished and when thermodynamics is seen as the effective description of a very

large number of these microscopic constituents in terms of a very few macroscopic

thermodynamic degrees of freedom. But such a perspective would hardly have been

justified at the times (middle of 19th century) when the first law was established.

At that time, atomism was only a conjecture, ...