56 SCIENCE PROGRESS 



representative of terpineol in the meta series, and is expressed 

 by the following formula : 



CMe C H 



Ch/ \cH.CMe 2 .OH 



CHa CH 2 



When treated with hydrogen chloride it is converted into 

 ^/carvestrene dihydrochloride which melts at 72 and is identical 

 with the hydrochloride formed by natural sylvestrene. The 

 hydrocarbon is isolated from this compound by heating it 

 with aniline ; it is represented by the formula l given below : 



CMe C H 

 CH 2 < >CH . CMe : CH 2 



CH 3 CH 2 



Perkin has also made some advance in the production of 

 lower homologues of the terpenes. The hydrocarbons pre- 

 pared up to the present belong to two types. One of these 

 is derived from cyclohexene containing no methyl group in 

 the ring 2 : 



CH, C H 



C 9 H„ or CH 2 / \c . CMe: CH 3 



CH 2 CH 2 



The other is framed on a cyclopentene containing a methyl 

 group 3 : 



C 9 H 14 orCH^ \CH.CMe:CH 2 



CHMe 



Both these substances are liquids possessing a lemon-like 

 odour, and they absorb oxygen with great rapidity in contact 

 with air. 



A hydrocarbon which has the composition C 9 Hi 4 exists in 

 the lower fractions of the oil from sandal wood, but its consti- 

 tution must for the present be regarded as unsettled. 



It is unnecessary to pursue this part of the subject further. 

 It is sufficient to point out that the natural terpenes, Ci H 16 , so 



1 Proc. Chem. Soc. [1910], 97. 



3 Matsubara and Perkin, Trans. Chem. Soc. [1905], 661. 



3 Haworth and Perkin, Trans. Chem. Soc. [1908], 573. 



