448 Mr. Gervaise Le Bas on the 



The volumes are : 



W. M.Y. 2A.V. A. 



Camphor, C 10 H 16 O" (0 =3H) ... 59 187-7 218-3 -30-6 



Borneol, C 10 H 17 OH (0' = 2H) ... 60 190*5 222-0 -31'5 



The contractions are very much increased in the bridged rings, 

 viz., about double of that for a single six-membered ring. 



It is thus not difficult to arrive at a knowledge of the 

 volume of Camphene, C 10 H 16 : 



CH 2 CH CH 



I 

 CH 3 C CH3 



I 

 CH 2 C CH; 



■CH, 



Calculated volume of Camphene : — 



C 10 H J? 56x3*370 = 207-2 

 Less for Ring — 31*0 



SA.V 176-2 



The Sesquiterpenes, C 15 H 24 . 

 It is well known that many o£ the terpenes and polyterpenes 

 stand in an interesting genetic relationship to Isoprene C 5 H 8 , 

 in that they are formed from the latter or some similar 

 open-chain di-olefin by polymerization. 



(a) Thus Isoprene C 5 H 8 is an open-chain di-olefin with 

 the formula 



CH 2 W.28. VC 5 H 8 ... 28x3-7 = 103-6 



^C-CH = CH 2 Observed... 103-9 



CH 3 (Thorpe). 



(b) The next stage is the formation of a Terpene, 



CH., CH,--CH, CH, CH,-CE, 



^s // ' % %. / \ 



,c - ch c-- ch 3 -> ;c - ch j: - gh 3 



,ch 3 Gh 2 =ch ch 3 n ch 2 -ch 



2 mols. Isoprene. Di-Pentene 



YC 10 H l6 (Di-Pentene) ... 192*8 (obs.) 



VGA- 56x3-70 = 207-2 

 Less for Ring — 15'0 



SA.V 192-2 



