March 8, 1895.] 



SCIENCE. 



271 



Eine Discussion der Krdftc der chemischen Dij- 

 iHimik. 3 Vorti-iige von Dr. Ludwig Stet- 

 tenheimer. H. Bechhold. Frankfurt, 

 1895. (5 Marks. 



Tlii.s pamphlet of 85 pages is certainlj' 

 revolutionary in character, as the author 

 proposes to aliandon some of our fundamen- 

 tal conceptions of chemistry, and to deal 

 with the subject purel J- mechanically. Chem- 

 istrj', according to the author, is the me- 

 chanics of the smallest bodies, as Astronomj' 

 is the mechanics of the largest, while Phjs- 

 ics is a connecting link between the two. 

 In chemistry we have to deal with mat- 

 ter, with equilibria, and with forces. In 

 chemical reactions energy is set ft-ee, and 

 we know in many cases its mechanical ex- 

 pression in calories. All the groupings and 

 unions which we expi'ess in our chemical 

 formuhe do not necessarily have their coun- 

 terpart in the substances themselves, but are 

 only conditions of eqnilibrium, not general 

 but special cases of equilibria. The mole- 

 cule ceases to be a fundamental conception. 

 Chemistry of to-daj- isa molecular chemistry, 

 but we must now give up this conception, 

 and, in the jjlace of the molecular or chem- 

 ical compound, we must introduce, as in as- 

 tronomy, a ' system,' a ' chemical system.' 

 Atoms combine to form groups due to the 

 action of the various forces, but why not 

 have these groups go on combining until we 

 have something which can be perceived l)y 

 the senses? If the same force of attraction 

 which binds the atoms together also causes 

 the groups to unite, \\hat conditions the 

 limits of the molecule ? In a substance like 

 potassium oxide we do not know whether 

 two or several molecules are combined, but 

 why may not hundreds, thousands or all 

 the molecules be combined? This does 

 not conflict with Boyle's law, since we may 

 regard a gas as if it were only one molecule 

 and having no inter-molecular spaces. 



A system composed of a few well-defined 

 atoms and gi-oups is termed a molecular 



system. These combined systems, and not 

 the ordinary molecules, represent conditions 

 of equilibria. In the second chapter c(m- 

 siderable space is given to the consideration 

 of equilibria, both stable and unstal)le, and 

 the third and last is devoted to the condi- 

 tions of union in the solid, liquid and 

 gaseous states. As a result of these con- 

 siderations, the author concludes that 

 chemical forces differ in no wise from me- 

 chanical, but that everything points to a 

 mechanical interaction between the smallest 

 particles of matter. 



While scientists are always readj' to con- 

 sider new ideas which will lead to wider 

 generalizations, yet it is always a fair ques- 

 tion to ask whether a given suggestion will 

 accomplish this. In the i^resent case it 

 seems quite proper to consider whether all 

 the chemical evidence of the existence of 

 atoms and groups forming definite units, 

 ciilled molecules, has been taken into ac- 

 count. If so, then will this method of 

 regarding chemical phenomena- enable us to 

 advance further or faster than that involv- 

 ing atoms and molecules ? It can tie safely 

 predicted that chemists will be somewhat 

 adverse to giving up conceptions upon which 

 their whole science is built, at least until 

 something more than abstract ideas are 

 offered in their place, something about 

 which they can think definitely and clearly, 

 and which will suggest new lines of work. 

 It is doubtful whether the work published 

 by Dr. Stettenheimer will meet with pro- 

 nounced success in removing these con- 

 ceptions of atoms and molecules from 

 chemistrj', since they have proved so fruit- 

 ful in the past, and seem to meet the de- 

 mands of most of the working chemists of 

 to-daj'. 



The book, while clearly printed, contains 

 a remarkablj' large number of typographical 

 errors. Nearly a full page of corrections is 

 given, yet the reader will encounter manj* 

 mistakes in the text which form no }iart of 



