November 11, 1910] 



SCIENCE 



655 



1. Would it be judicious to establish a differ- 

 ence between the term aiom and moleculet 



2. Would it be judicious to designate by the 

 term molecule the smallest quantity of a body 

 capable of entering into combination? 



3. Would it be judicious to designate by the 

 word aiom the smallest quantity of a body exist- 

 ing in combination? 



4. Should the term compound atom be sup- 

 pressed and replaced by the words residue or 

 radical? 



5. Is the idea of equivalents empirical and in- 

 dependent of the idea of atom or molecule? 



Kekule spoke upon the first three questions. 

 He laid emphasis on the necessity for distinguish- 

 ing between atom and molecule; furthermore, he 

 insisted at some length upon the distinction which 

 should be established, in his opinion, between the 

 physical and chemical molecule, which are not 

 always identical. He advanced the opinion that 

 the size of the chemical molecule would always be 

 of value in assisting purely chemical researches, 

 and without the aid of any physical considera- 

 tions. 



Cannizzaro, in an impromptu address remark- 

 able for profundity and style, combated the ideas 

 of Kekule. He opined that the chemical and phys- 

 ical molecules were absolutely identical — that 

 they could not be distinct one from the other. 

 The gaseous molecule represented the chemical 

 molecule, and it was impossible to conceive any 

 other idea of a molecule. Secondly, the value of 

 the chemical molecule could only be established 

 in a certain manner, that is to say, by the vapor 

 density, which alone could serve to establish the 

 true formula of a compound. 



Wurtz suggested that the congress should with- 

 hold any decision upon the distinction raised 

 between the physical and chemical inolecule. He 

 thought that upon the first three questions they 

 would all agree, so he passed on to the fourth 

 proposition. Many chemists, among them Can- 

 nizzaro, Miller, Kekule and Persoz, spoke upon 

 this subject, and their opinions were divergent. 

 Therefore, after a very long discussion, the de- 

 cision was adjourned, especially since the assem- 

 bly appeared to be divided as to the resolution 

 which they should come to. It should be men- 

 tioned here that the entrance of the illustrious 

 Dumas, whose advent before the conclusion of the 

 meeting was greeted with loud applause, did not 

 apparently conduce towards an agreement on the 

 question under discussion. On the fifth proposi- 

 tion of the commission being presented, it was 

 put to vote and adopted. 



On the fifth of September, with Dumas in the 

 cnair, the following propositions were presented 

 for consideration: 



1. Would it be desirable to place chemical nota- 

 tion in harmony with the progress of science? 



2. Would it be judicious to adopt the principles 

 of Berzelius, with the introduction of the neces- 

 sary modifications? 



3. Should any new signs be added to the num- 

 ber of symbols now in use? 



Cannizzaro spoke first. The first question, he 

 asserted, only required asking to be answered. 

 An ardent defender of the unitary system, he did 

 not see that it was necessary to preserve the nota- 

 tion of Berzelius, but would adopt that of Ger- 

 hardt. A compromise which would modify the 

 binary system so as to introduce part of the 

 unitary system seemed to him quite inadmissible; 

 it would oblige chemists to resort to retrogres- 

 sion. It seemed preferable to him, therefore, to 

 start from Gerhardt's theory, and to discuss his 

 plan and modify it in parts if found necessary. 

 The eloquent chemist of Genoa then discussed the 

 fundamental ideas of the unitary system; in his 

 remarkable plea in favor of the theories of Ger- 

 hardt, he was obliged to show the impossibility, 

 in the actual state of science, to adopt any other 

 notation than that of the unitary system. He 

 concluded by requesting of all to admit at least 

 in principle the new notation, and consequently 

 employ the barred letters to represent the simple 

 bodies corresponding to two volumes. 



Strecker, Kekule, Will, Erdmann and Kopp 

 spoke successively, some to corroborate the proofs 

 given by Cannizzaro and to strengthen the doc- 

 trine which he defended, and others to combat it. 

 All agreed, however, to adopt the use of the barred 

 letters. Dumas considered that the time had not 

 yet arrived to adopt a definite mode of notation; 

 he expressed the desire that the modifications 

 which were rendered necessary by the recent prog- 

 ress of chemistry be added to the system of 

 Berzelius, while awaiting the final settlement of 

 the question. One necessary point to which he 

 directed the attention of the congress was the 

 importance of looking at the requirements of 

 instruction. In this respect, unity of language 

 and theory seemed to be most desirable. There- 

 fore, by an entire freedom in the drawing up of 

 scientific memoirs the professors should endeavor 

 to smooth as much as possible the difficulties 

 produced by the divergence in these theoretical 

 ideas. 



To summarize the results of this congress, it 

 may be sr,id that every one present was agreed 



