242 
ME. C. GEEVILLE WILLmiS OX ISOPEEXE AXD CAOETCHIXE. 
! Name of observer. 
Fluid found. 
Boiling-point. 
Density. 
Liquid. 
Vapour. 
Gregory 
Bouchardat 
Bouchardat 
Bouchardat 
Himly 
Himly 
Bouchardat 
C“H“ 

Caoutchene (C° H“) 
Eupione (?) 
HU?) 
Caoutchine (C^®H^®) 
Heveene (C" H") ... 
O 
36 
below 0 
14-5 
51 
30—40 
171 
above 315 
0*654 
0*630 at 4^ 
0*650 
0*690 at 15° 
0*842 
0*921 at 21° 
4*461 
Results so contradictory would almost lead one to suppose that, like castor oil. 
caoutchouc yielded different products according to the temperature, but in that case 
the distillate obtained in a carefully conducted experiment should contain bodies 
belonging to the oletiants and the terebenes ; this, however, is not the case. The 
weight of evidence appearing to prove olefiants to be the principal products, I had some 
hopes that caoutchouc, if carefully distilled, worrld yield hydrocarbons from which I 
might obtain certain at present unknown hydriodic ethers and their derivatives, in 
accordance with reactions first imagined by M. Berthelot, thrrs : — 
C“H“ + HI = (C“H°+*) + I 
V ) V ^ ^ ) 
Olefiant plus Iodide of alcohol 
hydriodic acid. radical. 
Brrt I soon found that caoutchouc, when carefully distilled in iron vessels, yielded no 
olefiant whatever. This is, moreover, in perfect accordance with experiments made by 
me some years ago*, hr which I showed that caorrtchouc, like many other oils, deco- 
lorized the same quantity of bromine as oil of tur’pentine. A repetition of this experi- 
irrerrt, made with great precaution to ensrrre success, will be forrrrd firrther on. 
The distillation was conducted with eare in arr hon alerrrbic, the lowest teirrperature 
beirrg used consisterrt with the distillation of oils. In fact I even stopped the distilla- 
tiorr before the whole of the last oil, heveerre, came over, irr order to ensrme the decom- 
position taking place irr the simplest marrrrer. The crrrde distillate was very foetid, 
arrd contained traces of volatile bases derived frorrr the decompositiorr of a mirrrrte trace 
of vegetable caseiire in the caoutchorrc. The bases were removed by agitatiorr of the oil 
with dilute sulphirric acid ; the latter was therr got rid of by washing with water, wirich, 
irr its trrrrr, was subsequently reirroved by digestioir with sticks of potash. The flrrid thus 
prepared was easily separated by fractional distillatiorr irrto tw’O portions, orre boiling 
betweerr 37° arrd 44° C., and the other betweeir 170° arrd 180°. The fr-actional separa- 
tioir of the hydrocarborrs hr the crude distillate affords a very irrstnrctive example of the 
extraordinary extent to which boiling-poirrts are low'ered by successive rectificatioirs. 
In the first rectification the product was very small, below^ 116° C. The greater part 
* “ On a Process for estimating the Equivalents of some Fluid Hydrocarbons by means of Bromine,” 
Chemical Gazette, 1853. 
