December 25, 1896.] 



SCIENCE, 



933 



effect this. " If the physicists and the 

 chemists work each in their own field and 

 with their own methods, a large area be- 

 tween the two will remain untilled, viz., 

 all that which can be cultivated only by 

 the simultaneous application of both meth- 

 ods of work. That physical chemistry 

 finds here an enormously large and fruit- 

 ful field for activity is distinctly shown 

 by the scientific advances of the last de- 

 cade." 



One may fairly ask why has this point of 

 view presented itself for the first time, in 

 the last few years ? This is the answer : 

 '' In the fifty years previously referred to, there 

 were discovered a number of general natural 

 laws, which were particularly important and 

 usefid because of their simplicity. These made 

 it possible for the investigator to comprehend a 

 very large number of facts in a few words or for- 

 mulce. " It has thus become relatively easier 

 for the physicist and chemist to know some- 

 thing of that science which belongs more 

 directly to the other. In reality, such 

 knowledge has become necessary on the 

 part of both. The physicist cannot under- 

 stand electrical phenomena and thermody- 

 namics without a knowledge of the law of 

 chemical mass action and an intelligent 

 comprehension of purely chemical phe- 

 nomena. The chemist, in turn, must have 

 a fair knowledge of electricity in order to 

 comprehend electro-chemical processes. In- 

 deed the inter-relation of physics and chem- 

 istry has become so pronounced that a 

 specialist in each can work over only a 

 limited range without having to take the 

 other into account. The remainder of this 

 interesting address is devoted more partic- 

 ularly to a discussion of the nature of the 

 work which it is proposed to carry on in 

 the new laboratory in Gdttingen. 



In connection with what has already been 

 accomplished by physical chemists since 

 their branch has become a distinct science 

 (which is hardly more than a decade), it 



seems desirable to call attention to some of 

 the generalizations which have been reached 

 by them; and what is so important in phys- 

 ics, and especially in chemistry, as a gen- 

 eralization, which brings together and in- 

 terprets at least a few out of that chaos of 

 facts whose real sigaificauce and meaning 

 are for the most part unknown. 



The generalization of van't Hoff that 

 ' optical activity ' is due to the presence of 

 an asymmetric carbon atom, was the foun- 

 dation for all the recent developments in 

 stereochemistry in the hands of Wislicenus, 

 Hantzsch, Werner, Y. Meyer, Auwers and 

 others. His application of the gas laws to 

 solutions, and its counterpart, the Arrhe- 

 nius theory of electrolytic dissociation, have 

 a significance the breadth and depth of 

 which are just beginning to become appa- 

 rent. Further, his studies in chemical dy- 

 namics, though less known, are probably his 

 greatest achievements. The work of Ost- 

 wald is of too general a character to specify 

 details. We owe to him preeminently the 

 systematic classification, into a science, of 

 those facts which it required a century 

 to ascertain. Scarcely less interesting are 

 the theoretical deductions of Nernst, who 

 has pointed out the real source of the elec- 

 tromotive force in Voltaic and other ele- 

 ments, so clearly and correctly that our ideas 

 in regard to primary batteries have been 

 largely revolutionized since the appearance 

 of his well known paper in 1889. From the 

 theoretical side we must not forget the ap- 

 plication of thermodynamics to physics and 

 chemistry by Horstmann and J. W. Gibbs, 

 and the wide significance of the law of Mass 

 Action, even should they date from a slightly 

 earlier time. And hardly less important 

 than the theoretical advances which we owe 

 already to physical chemistry are the ex- 

 perimental. One need mention only the 

 work of Raoult and Beckmann on freezing 

 points and vapor tensions, of Le Blanc on 

 polarization, of Ramsay and Shields on 



