THE GROWTH OF CHEMICAL IDEAS 131 



years before the study of reaction velocities was resumed. 

 Then, in 1867, the full significance and generality of the 

 problem were recognized by two Norwegian scientists, C. M. 

 Guldberg and P. Waage. They stated that the velocity of a 

 reaction at constant temperature is proportional to the prod- 

 uct of the active masses of the reacting substances, this being 

 the fundamental law of chemical kinetics, which is generally 

 called the law of mass action. 



With the discovery of this principle, many chemists 

 turned their attention to the velocity of reactions, which soon 

 centered upon the phenomenon of catalysis. This term had 

 been introduced by Berzelius for reactions the velocity of 

 which was greatly increased by the presence of small amounts 

 of foreign substances that apparently took no part in the 

 reaction and underwent no chang^e. The conversion of starch 

 into sugar, for instance, is accelerated by dilute acids. Hy- 

 drogen peroxide decomposes rapidly in the presence of finely 

 divided platinum, which also assists the oxidation of ethyl 

 alcohol to acetic acid. Berzelius said: "I don't believe that 

 this is a force quite independent of the electrochemical af- 

 finities of matter, but since we cannot see the reaction and 

 mutual dependence, it will be more convenient to designate 

 the force by a separate name." That name was catalysis. 



\Vg have seen that Wilhelmy discovered the laws of chem- 

 ical kinetics in the study of the inversion of cane sugar, which 

 was catalyzed by acids. It was at Wilhelm Ostwald's labora- 

 tory at Leipzig, sixty years after the work of Berzelius, that 

 the study of catalytic phenomena was systematically brought 

 into the domain of chemical kinetics and investigated quanti- 

 tatively. Ostwald founded the greatest school of physical 

 chemistry and brought together the work of Guldberg and 

 Waage, of Willard Gibbs, J. H. van't Hoff, Svante Arrhenius, 

 and W. Nernst in his great textbook of general chemistry, 

 which, with the Zeitschrift filr physikalische Chemie^ sup- 

 plied the written sources through which physical chemistry 

 could be taught to the student. 



Just as the work of Guldberg and Waage supplied the key 



