410 Mr. S. A. Sworn on the Constitution 



Symbols such as 



and 



( P TTO 



would lead to the constitution C 10 H 4 < p 3 TT 2 for pyrene- 



quinone, whereas experiment shows that this body must be 



f TT O 

 represented as C 10 H 4 < p 3 TT 2 ry (^ ee PJ ren ^ c ac ^ & c -? Ber. 



xx. p, 371.) 



On the other hand, these bodies can be readily represented 

 as conjugations of Thomsen's symbol (vide infra for adapta- 

 tion of Meyer's symbol). 



C H 



CH 



CH 



CH 





CK 



'l 



CO 



CH 



- C 



\c/^ 



c 





D^> 





<^B 



CH 



C 



^XX^ 



c 





CO 





CH 



CH 

 CH 



Pyrene, C 16 H 10 . 

 (Compare symbol on p. 



CH 



Pyrenequinone, C 16 H 8 2 (a naphtha- 

 .) lene deriv.). {Vide infra, 



constitution of benzoquinone.) 



The facility with which they can be thus represented affords 

 further evidence of para- as opposed to double-linkage. 



Here we may pause to consider the views of those chemists, 

 who, in spite of recent research on the causes which deter- 

 mine isomerism, have refused to believe that in the symbol of 

 Claus the para- are to be distinguished from the ortho-di- 



