518 



Agreeing perfectly with the formula C 20 H 14 *. 



134 100-0 



Paracymole. 



At the same time that cymole is formed, there is a production of 

 an oil having the same composition, but boiling about 300 C. The 

 author has provisionally named it paracymole. 



Action of Sulphuric Acid on Caoutchine. 



Sulphuric acid acts on caoutchine, converting it almost entirely into 

 a viscid fluid like heveene, at the same time a very small quantity of a 

 conjugate acid is formed, having the formula 



C 20 H I6 S 2 O 6 ; 



the composition was determined from that of the lime salt, which on 

 ignition, &c., gave a quantity of sulphate of lime equal to 8'3 per 

 cent, of calcium ; C 20 H 15 Ca S 2 O 6 requires 8'5. 



The author considers the action of heat on caoutchouc to be merely 

 the disruption of a polymeric body into substances having a simple 

 relation to the parent hydrocarbon. He deduces this view from the 

 similarity in composition between pure caoutchouc, isoprene, and 

 caoutchine. 



The following Table contains the principal physical properties of 

 isoprene and caoutchine : 



Table of the Physical Properties of Isoprene and Caoutchine. 



In the calculations rendered necessary by the numerous vapour- 



* (Note received July 27.) Both the cymole from turpentine and that from 

 caoutchine were converted into insolinic acid by bichromate of potash and sul- 

 phuric acid. The quantitative determinations made on the silver salt of the acid 

 were almost theoretically exact. 



