Theory of Molecular Volumes. 



449 



(c) The third stage is the bridging of the ring by some 

 means, so as to form a Oamphan Terpene. 



CH 5 



CH 

 I 



CH 



CH 3 C CM3 

 I 



CH 2 C CH 



I 

 CH 3 



VCh)H 16 ... 56x3-70 = 207-2 



Less for double Bino- — 31 '0 



2A.V. 



176-2 



The last stage was accomplished without any addition of 

 matter — only a bridging of the ring. 



The question now is, whether the Sesquiterpenes C 15 H 24 

 are formed directly from the Menthan class of terpenes 

 (by the addition of a molecule of isoprene C 5 H 8 ), or 

 whether the third stage — the bridging of the ring — first 

 occurs ? 



The answer to this will depend on whether the sesquiter- 

 penes C15H24 contain three rings or two. Doubtless there 

 are many varieties of structure among a class of compounds 

 like the sesquiterpenes, but in their physical properties they 

 are very similar. 



Compound. 



<*15-5- 



B. P. 



Cadinene 



...' 0-921 



275° 



262 



261 



264 



254 



254 



264 



270 



258-9 



Clovine 



0-932 



Cedrene 



Ledene 



Patchoulene 



Santalene cc 



0936 

 9349 

 0945 

 0-9034 



n 



Zangiberine 



Cannibene 



... 0-9039 

 ... 0-876 

 ... 0-898 



If we consider Quinolcne C 9 H 7 N, d 1-1055, d BF '9211, 

 B.P. 232° C, we obtain a value of '433 for K. The hydrogen 

 content of the sesquiterpenes is greater, so that the value of 

 K is a little higher, 0*0450. It should be mentioned that a 

 difference of 10 per cent, in the value of K involves a 

 divergence of only 1 per cent, in the actual volumes. It 

 follows that the effect of slight divergences in the value of K 

 only very slightly affect the volumes. 



Phil Mag. S. 6. Vol. 28. No. 166. Oct. 1914. 2 G 



