PREFACE TO VOLUME I 





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The present Volume of the Commentary deals with Gibbs' 

 thermodynamical papers, and principally with the famous 

 paper on The Equilibrium of Heterogeneous Substances. In this 

 immortal work, Gibbs, building on the sure foundations laid by 

 Carnot, Mayer, Joule, Clausius and Kelvin, brought the science 

 of generalised thermodynamics to the same degree of perfect 

 and comprehensive generality that Lagrange and Hamilton had 

 in an earHer era brought the science of generaUsed dynamics. 



The originality, power and beauty of Gibbs' work in the do- 

 main of thermodynamics have never been surpassed. The gen- 

 erahty and abstract nature of the reasoning have, however, 

 made the understanding of his methods and results a difficult 

 task for many students of science. This has been particularly 

 true of students of chemistry, who in general are deficient in 

 mathematical training and are not as a rule familiar with the 

 methods and results of generafised classical dynamics — a very 

 necessary mathematical precursor to the study of generafised 

 thermodynamics. This state of affairs has been very unfor- 

 tunate in the past, since the work of Gibbs contained a complete 

 and perfect system of chemical thermodynamics, i.e., a system 

 of thermodynamics peculiarly well adapted to the most general 

 and complete application to chemical problems. What, for ex- 

 ample, could exceed, in simplicity and generality, Gibbs' expres- 

 sions, in terms of his chemical potentials, for chemical equilibrium 

 in a homogeneous phase or the distribution equilibrium of inde- 

 pendent components throughout a system of coexistent phases? 



Although the physicist will undoubtedly find much of the 

 greatest interest and value in the present volume, this Com- 

 mentary is intended for the use of students of physical chemistry 

 as well as physics. The Articles contained in it are not there- 

 fore merely running comments on and illustrations of Gibbs' 

 equations, but constitute in each case a thoroughgoing discus- 

 sion of the corresponding part of Gibbs' work, the object of 

 which is so to smooth the path for the reader of the original 



