290 THE REVIVAL OF INORGANIC CHEMISTRY. 



Since 1SS2, thanks to the labors and. inspiring influence of Ostwald, 

 van't Hoff, Arrhenius, Nernst, and others, physical chemistry is no 

 longer the chemistry of the future merely, but of the present, and apart 

 from the quickening influence which it is exerting in nearly all branches 

 of chemistry proper, both pure and applied, we are beginning to per- 

 ceive that we are entering a period in which chemistry will be of greater- 

 service to the allied sciences. Geological chemistry is showing signs of 

 reviving under the stimulus of physieo chemical conceptions, and we 

 are finding, too, that as physiological chemistry is not merely the chem- 

 istry of sugar, or urea, or albumin, but preeminently a science of moving 

 and changing molecules, it can only progress by the aid of a knowledge 

 of the laws of chemical energy. 



The achievements of physical chemistry form, perhaps, the most 

 interesting phase of the recent history of our science, but its followers 

 have spoken for themselves so often of late years, and have presented 

 the subject so much better than I could do it, that I feel compelled to 

 consider a perhaps humbler, but yet not unimportant, field of research, 

 which, in a sense, may also be called a part of the chemistry of the future, 

 the field of Inorganic Chemistry. The relations of physical and inorganic 

 chemistry have recently been discussed by van't Hoff in his admirable 

 address delivered last summer beiore the Society of German Scientists 

 and Physicians, and I shall, therefore, limit myself to the consideration 

 of a few points of a more strictly chemical nature, touching the rela- 

 tions of physical and inorganic chemistry only incidentally. 



The aim of physical chemistry will have been accomplished when it 

 has established a mathematical equation which, by proper substitution, 

 will enable us to predict the nature of every possible chemical system 

 or reaction, and the properties, physical and chemical, of every possi- 

 ble element or compound. Until he has reached this chemical millen- 

 nium, unless he will risk falling into the pit which has received so many 

 philosophers in the past, the chemist must continue to advance by the 

 route by which our understanding of every other branch of physical 

 science has been reached. Notwithstanding all that physical chemis- 

 try can do with this material at present in hand, the experimenter must 

 long continue to take the short cut to knowledge and find out what his 

 elements and compounds will do by first actually getting them in hand, 

 by precipitation, filtration, distillation, crystallization, and the like. It 

 may be questioned whether our present knowledge of facts would ever 

 suffice to enable us to predict, for example, a single atomic weight with 

 accuracy, or to explain that wonderful relation between properties and 

 atomic weights known as the Periodic Law. A few enthusiastic physi- 

 cal chemists have spoken slightingly of the compound maker as a kind 

 of inferior being, apparently forgetting that it is just this kind of pio- 

 neer work which has supplied the material for their labors, that the 

 first requisite for successful generalization is the possession of a large 

 number of pure substances, of accurately known composition and prop- 



