58 WILSON 



ART. C 



efficiency, so dear to the engineer, nor of that of availabihty of 

 energy, upon which some authors base their discussion of en- 

 tropy; as the equivalents of these ideas must be imphed in any 

 development of the subject, it is only the terminology and view- 

 point, not the essentials, which were omitted. He dealt at 

 length with the properties of the thermodynamic surface, but 

 did not cover all the detail which was included in his second 

 paper; there was no particular reason why all of it should be 

 covered. 



As for what we find in the current literature with respect to 

 the subject matter of these two initial papers one may state that 

 the temperature-entropy diagram is now treated at length in 

 engineering treatises on the steam engine* in which many 

 detailed illustrations, both graphical and numerical, may be 

 found. Physicists and chemists do not seem to use the temper- 

 ature-entropy diagram to any great extent. The thermo- 

 dynamic surface was perhaps given more attention by Maxwell 

 in his little book on Heat (4th edition) to which reference has 

 been made than is now customary with writers of texts on the 

 physics or chemistry of heat.f This neglect is certainly not due 

 to any failure to appreciate the contributions of Gibbs any more 



* See for example the article on the Steam Engine in the Encyclopedia 

 Britannica or the treatise An Introduction to Thermodynamics for En- 

 gineering Students hy John Mills (Ginn and Co.) or Thermodynamics of 

 the Steam Engine and Other Heat Engines by C. H. Peabody (John Wiley 

 and Sons) . It is far from clear that the use of the temperature-entropy 

 diagram in such works derives directly from the presentation in Gibbs' 

 Paper II. 



t For example, in the excellent Einfuhrung in die theoretische 

 Physik, Berlin, 1921, Bd. II, Th. 1, by C. Schaefer, the theory of heat is 

 presented in 562 pages. Yet the temperature-entropy diagram seems 

 not to appear, nor the thermodynamic surface to be mentioned. There 

 are fourteen references to Gibbs in the index, mentioning the following 

 topics: The Gibbs paradox of increase of entropy on mixing gases, the 

 total energy e, the phase rule, definition of components, the electro- 

 motive force of a cell, and statistical mechanics. None of these refer- 

 ences is to Paper I or II. In the Thermodynamics of G. N. Lewis and 

 M. Randall, McGraw-Hill, 1923, there is equal citation of Gibbs for much 

 the same topics but again no mention of the i77-diagram or thermo- 

 dynamic surface. 



