( '1-t ) 

 '!Di =Q. ('IT\ =(^1 , IVl!.'^ ^ 1 (dT\ luy 1 



. /(^■■'7'\ 3 fdT\ 

 and — — = — — . In this it is noteworthy, tliat on account of 

 \dx' J„ ,r„ \dxj^ 



Q = q + 



da 



a - x{\—.r) — 

 dx 



/ also 1^—1^0. 

 dx 



/'dT\ RT^" /d-'T\ 

 With (Si) we shall find from (ll): — h= TT" 5 VT = 



/ 2in\\fdT\ fdQ\ 



Chemistry. — '■'On ocimene and myrcene, a contrihution to the 

 knoivh'dye of the aliphatic terpenes." By Dr. C. J. Enklaar. 

 (Communicated by Prof. P. van Romburgh). 



(Communicated in the meeting of Januari 27, 1906). 



The aliphatic terpeiie group, discovered in 1890 by Semmler '), is 

 characterised by the absence of closed rings ; the terpenes of this 

 group possess, therefore, three double links in an open chain. The 

 first aliphatic terpene described was anhydro-geraniol, which Semmler 

 prepared ") from the aliphatic terpene alcohol geraniol by heating 

 the same with potassium hydrosulphate. This terpene has not yet 

 been obtained pure, and has been but little investigated. A naturally 

 occurring tei'pene of this group was found by Power and Kleber ') 

 in oil of Bay (the ethereal oil of Myrcia acris D. C); it was called 

 by them myrcene. The sp. gr. (0,801 at 15°) was much lower than 

 that of the cyclic terpenes (0,840 — 0,860), the molecular refraction 

 and the addition of bromine pointed to the presence of three double 

 links. With permanganate myrcene yielded some succinic acid, on 

 treatment with mixed sulphuric and glacial acetic acid an alcohol 

 was obtained, having the odour of oil of bergamotte, Avhich was 

 taken for linaloöl on account of its oxidation to citral. Myrcene oxi- 

 dised in contact with the air, and polymerised even at the ordinary 

 temperature. In his studies on caoutchouc Harries *) has for some 

 time considered these polymerisation products as closely allied or iden- 



1) Ber. 23, 2965 (1890), and 24, 201 and 682 (1891). 



■') Bar. 24, 682 (1891). 



3) Pharm. Rundschau (New- York) 1895, no. 18. 



*) Ber. 35, 3256 (1902). 



