THE CHEMICAL PROBLEMS OF TO-DAY. 363 



tioned ideal. And thus it happens that in the chemistry of to-day im- 

 agination and intuition have a larger scope than in other sciences, and 

 that occupation with the same, besides the pure scientific satisfaction 

 that it yields, brings an enjoyment which, in a certaiu sense, reminds 

 one of the activity of an artist. He however who only knows chemistry 

 as a tradition of perfectly clear facts, or who thinks to see the real soul 

 of chemical study in measuring the 7>/<//.sic'rt/ phenomena which accom- 

 pany chemical transformations, feels no breath of this enjoyment. 



The feeling is only disclosed to him who ventures into that ocean of 

 the unknown that is spread out before us in the orf/anio chemistry of the 

 day; to him who is not a[)palled by a wilderness, populated with 

 thousands of indivuals, of which every one shows a peculiar, fully 

 unknown originality, and to him who attempts to become better 

 acquainted with some of them, even if he is at a loss for a means of 

 approaching tliem. To proceed with success in this direction is only 

 granted to the genius; the method that leads onward can not be 

 learned, and it has only been practiced with success by a small number 

 of chosen ones. 



Indeed, in the experimental study of organic chemistry, the " pre- 

 sentiment" of happenings, the actuality of which is not indicated by 

 any law to be expressed in words, has shown surprising results ; here 

 the thought is aided by a something, which we may meanwhile term 

 "chemical feeling," a name which will disappear as soon as the pro- 

 gressive approach of chemistry to the mathematical physicil basis 

 shall have disclosed its meaning and shall have tabulated it amongst 

 the methods which lead to the recognition of the new. The efiect of 

 this ])eculiar chemical method of study is not here to be dwelt upon in 

 detail. Let it suffice to say that without it, the most brilliant discov- 

 eries in organic chemistry would not have been made: just as little 

 as a Kekule would without it, have been able — in contradiction of 

 numerous data in chemical literature never before doubted — to affirm 

 the non-existence of isomeric monochlorbenzol and of such bodies as 

 were said to consist of a benzol ring and but one bi-valentatom. Those 

 significant hypotheses by means of which the knowledge of aromatic 

 substances has been revealed to us, could not have been made solely 

 upon the ground of exact observation ; they required at the same time 

 a pronounced chemical instinct. There was no logical reason iu declaring 

 the existence of a phenylene oxide as an impossibility, since the ethylene 

 oxide did exist ; he who nevertheless ventured to do so, and at the 

 same time ran directly in the face of experience, was surely led by a 

 feeling which the present status of chemistry forbids us to replace by 

 a process of thought. 



But to return from the field of organic to that of general chemistry. 

 Before we can arrive at a mathematicophysical treatment of chemical 

 phenomena iu general, two fundamental problems nnist be solved ; an 

 hypothesis which allows a control by experiment (even within the same 



