OP ARTS AND SCIENCES. 71 



satisfactory till a later paper,* in 1879). Anschlitz and Japp oxidized 

 the sodic salt of the phenanthrenesulphoacid wilh potassic permanga- 

 nate, and obtained phtalic acid as the only product, whereas, if phe- 

 nanthrene were not a diortho compound, isophtalic or terephtalic acid 

 must also have been formed. 



In 1871) Merz and Weith f proposed a new formula for phenan- 

 H H 

 threne, C^H^ =: C — C = Cgll^, founded on the fact tha.t they obtained 

 invariably perchlorbenzol instead of perchlordiphenyl by the exhaust- 

 ive action of chlorine upon it ; the formation of diphenic acid would 

 then be due to an atomic transformation during the process of oxida- 

 tion. This hypothesis, however, can hardly be considered as throwing 

 doubt on the constitution of phenanthrene until supported by addi- 

 tional facts, especially since Japp J has shown by the formation and 

 properties of the y8 phenanthrenecarboxylic acid that the C2H2 group 

 behaves as if it were part of a benzol ring. 



At present, then, the constitution of plienanthrene must be consid- 

 ered as settled, while it still remains to prove the position of the two 

 connecting atoms of carbon on one of the benzol lings in anthracene. 



Action of Sodium on Orthohrombenzylbromide. 



In the hope of settling the constitution of anthracene we have 

 studied the action of sodium on orthobrombenzylbromide, since this 

 might lead to the formation of a hydride of anthracene by the union 

 of two molecules, the side-chain of each being joined to the ring of 

 the other, and of phenanthrenedihydride if the two side-chains and 

 the two rings were united. As these two reactions were likely to take 

 place side by side, we expected that our product would consist of a 

 mixture of these two hydrocarbons. 



Orthobrombenzylbromide dissolved in anhydrous ether § was warmed 

 with sodium for some days, fresh shavings of sodium, or sodium shot,|| 

 being added from time to time, until the bright surfaces were no longer 

 tarnished. The greater part of the sodium was then removed, and, 



* Ber. (1. ch. G., '79, p. 235. t Ibid., p. 677. 



X Ibid., '80, p- 573. 



§ When toluol was used in place of ether, the reaction ran so slowly that 

 even after boiling for several days the sodium was but little affected. 



II The sodium shot was made by melting sodium under toluol, and shaking 

 (Wislicenus, Ann. Cliem. Phatra., clxxxvi. 212) It seemed not to be so effective 

 as thin shavings of sodium. 



