DEVELOPMENT OF GENERAL AND PHYSICAL CHEM- 

 ISTRY DURING THE LAST FORTY YEARS."^ 



By W. Nernst. 



Although in principle physics and chemistry follow the same 

 methods and look toward a common end, an end which, as Helm- 

 holtz has so aptly described it for physics, is " To assert by the 

 logical forms of laws our intellectual mastery over nature, at first 

 a stranger to us," nevertheless the diversity of the problems and 

 facilities has in practice necessitated a separation of the two branches. 

 Consequently the energies of the physicist and chemist have been 

 expended almost entirely on special problems in their own fields of 

 research, and as a result a large boundary region between the two 

 sciences remained neglected for a long time. Only in the period of 

 time which this sketch covers has there been any lively interest in 

 physical and theoretical chemistry. 



No one will deny that, as far as any theoretical mastery of matter 

 is concerned, physics has not for a long time made nor is even now 

 making any advances. Why this can not be otherwise is easy to un- 

 derstand. The physicist often needs relatively onl}^ a very small 

 amount of material to work on to derive immediately the fundamental 

 theoretical laws of the subject which he is investigating. For example, 

 it is only necessary to know the density of atmospheric air at a single 

 temperature and a single pressure to develop physico-mathematically 

 by the sole aid of the gas laws and the principles of the theory of 

 heat the rule of sound vibration, and from that the fundamental prin- 

 ciples of acoustics generally. How different and how much more 

 difficult are the problems which confront the chemist when he at- 

 tacks the study of atmospheric air, whether he attempts to determine 

 its composition down to the last particle or whether he investi- 

 gates the remarkable and complex equilibria which obtain at high 

 temperatures. 



Chemistry to-day can boast of a set of theoretical principles that 

 do not suffer in comparison with those of physics. What a mass of 



•* Address before the German Chemical Society at the celebration of the for- 

 tieth anniversary of the society, November 11, 1907. Translated, by permission, 

 from Rerichten der Deutschen Chemischen Gesellschaft. Jahrgang XXXX. Heft 

 17. Berlin, 1907, pp. 4617^626. 



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