194 



POPULAR SCIENCE MONTHLY. 



" I do not need to state that indus- 

 trial applications will not be the object 

 of the work. I have left my native 

 land because I know that in Germany, 

 more than elsewhere, we find wide- 

 spread the conviction that the pursuit 

 of knowledge for its own sake is the 

 highest aim of human efforts." 



phates of sodium, potassium, mag- 

 nesium and calcium. Although not yet 

 finished, the work is a masterpiece 

 and shows what can be expected from 

 an application of physical chemistry 

 to geology and mineralogy. 



The work of van't Hofi' can be divided 

 crudely into four parts: 1872-1877, or- 



PROFESSOR J. H. VAN'T HOFF, BERLIN. 



The special form of the problem was 

 a systematic study of the conditions of 

 equilibrium in their bearing on the 

 salt deposits at Stassfurt, but the gen- 

 eral results are applicable to all cases 



ganic chemistry; 1878-1884, chemical 

 affinity; 1885-1895, theory of solu- 

 tions; 1896-1904, oceanic deposits. 

 Much of the organic chemistry of to- 

 day is the direct outcome of the work 



in which the deposits consist chiefly of clone in the first period; the second and 

 any mixtures of the chlorides and sul- third periods made physical chemistry 



