xxxii Centennial Anniversary 



to understand, the paper of the other. Each has made a contri- 

 bution to the stock of human knowledge, and the Academy, with- 

 out committing itself to the conclusions of any of its members, is 

 glad to serve as a vehicle of transmission, by which such as it may 

 deem of sufficient importance may be communicated to the scholars 

 of the world. 



The estimation in which the publications of the Academy are 

 held by those to whom they are thus especially addressed may be 

 shown from a single though certainly a conspicuous instance. 



The three papers contributed by Professor J. Willard Gibbs to 

 the second and third volumes of our Transactions, on Thermody- 

 namics, and fresh modes of expression which Chemistry can bor- 

 row from Mathematics, have been uuiversallv recognized as con- 

 taming practical suggestions of the first importance, as well as 

 statements of certain laws never before distinctly formulated, as 

 to the properties and inter-relations of heterogeneous substances. 

 One of those (the law of phases) is now commonly known by 

 chemists as Gibbs' law. These articles were translated into Ger- 

 man by Professor Ostwald of the University of Leipsic, in 1892, 

 and a French version of one of them, (that in regard to the equi- 

 librium of heterogeneous substances), by Professor Chatelier of 

 the College of France, has appeared this year at Paris. In the 

 preface to this book, Professor Chatelier declares that the sym- 

 bolic representations of chemical substances or compositions pro- 

 posed by Professor Gibbs in the second volume of our Transactions 

 have already proved of inestimable service to science by opening 

 a way to the study of subjects so complex that it would have been 

 absolutely impossible to reach any intelligible result without the 

 aid thus afforded of what spoke to the senses and the imagination. 

 A new branch of chemistry, he says, has thus been created " dont 

 Pi??ijjortance, tons les jours oroissante, demerit aujourd'hui com- 

 parable d celle de la chimie ponder 'ale creeepar Lavoisier." * 



I need not comment on the comparison thus suggested between 

 the recent advance in chemical science flowing from the use of 

 Professor Gibbs' methods of investigation, and the great stride 

 taken in human knowledge when the " phlogiston " theory of Stahl 

 was replaced by the proposition of Lavoisier that nothing is lost 



* Equilibre des Systeines Chiruiques, Paris, 1899, vi. 



