ON THE PRESENT POSITION OF THE CHEMISTRY OF RUBBER. 257 



double bonds. This is in agreement with our knowledge of the halogen 

 addition compounds of caoutchouc. The view that caoutchouc contains 

 three double bonds is not in the least confirmed. The above formula also 

 agrees with the observed fact that rubber is optically inactive ; no asym- 

 metric carbon atom is present in the formula. 



Returning to the question of the fraction of the distillation products 

 obtained by Harries (p. 246), it was now found that on treating the 

 fraction boiling 160°-170°, which at the time he considered to be a new 

 hydrocarbon, with ozone, a glassy mass was obtained, having properties 

 similar to those of the ozonide of caoutchouc, and which gave levulinic 

 aldehyde on boiling with water. It would therefoi'e appear probable 

 that a liquid consisting of unpolymerised molecules of dimethyl octadiene 

 was contained in this fraction. 



Oxidation oj Indiaruhher in Air. 



J. Spiller ' investigated the effect of atmospheric oxygen on a thin 

 film of indiarubber. After exposure of the sample an oxygen-containing 

 product was isolated ; this was soluble in alcohol and chloroform, melted 

 below 100°, and possessed the following composition : Carbon, 64-0 per 

 cent.; hydrogen, 8*46 per cent. ; oxygen, 27'54 per cent. 



Weber (1902) pointed out that these figures agree approximately with 

 the formula C30H4SO10) oi" (CioH,6)3 + 50^, and considered that it was an 

 additive product. 



W. A. Miller,- in an account of his experiments on the decay of 

 guttapercha and caoutchouc, describes a soft viscous resin produced by 

 the action of air and light on caoutchouc after an exposure of nine 

 months. It was soluble in alcohol, and on analysis was sho'- to have 

 the composition : Carbon, 67'23 per cent. ; hydrogen, 9-54 per cent. ; 

 oxygen, 23'23 per cent. 



Edgar Herbst,^ by passing a current of purified air for 140 hours 

 through a hot solution of Para caoutchouc in benzene, obtained two sub- 

 stances : (1) a transparent reddish -brown syrup, soluble in light petro- 

 leum, having the composition C,oHigO ; and (2) an amorphous, friable, 

 yellow solid of the composition CioHigOj. The latter is sparingly soluble 

 in a mixture of light petroleum and benzene, and separates from this 

 solvent as a hard glassy mass with substantially different properties. 



The Study of ffydro-aromatic Sithstances. — Report of the Committee 

 consisting of I)r. E. Divers (Chairman), Professor A. W. Crossley 

 (Secretary), Professor W. H. Perkin, Dr. M. 0. Forster and 

 Dr. H. R. Le Sueur. 



1. The supposed Identity of Dihydrolaurolene and Dihydroisolaurolene 

 ivith 1 •.l-dimethylhexahydrobenzene. — In the last Report^ brief allusion 

 was made to the preparation of 1 : l-dimethylhexahydrobenzene,^ and it 

 was stated that the main object in view when preparing this hydrocarbon 



' Journ. Forts der Chem. (I8G0), 575. 



' J. C. S., 1865, 273. » Her., 1906, 39, 523-5. 



* Reports, 1905, p. 153. » Crossley and Eenouf, J. C. S., 1905,87, 1487. 



1906. 'a 



