ME. C. GEEVILLE WILLIAMS ON ISOPEENE AND CAOUTCHINE. 
251 
reagents; and it is worthy of observation that the resulting hydrocarbon has the same 
peculiar odour, from whichever source it is prepared 
In the following analyses, I. was made on a product from turpentine, II. was fraction 
5, and III. was fraction d. Fraction a was rejected, as it appeared to contain traces of 
the original hydrocarbon, regenerated in the same manner I have shown to taFe place 
with brominized heptylene and octylene. 
I. 0‘1550 gi-m. gave 0-5070 carbonic acid and 0-1466 water. 
II. 0-1918 grm. gave 0-6292 carbonic acid and 0-1790 water. 
III. 0-2100 grm. gave 0-6892 carbonic acid and 0-1968 water. 
Or, per cent., — 
Experiment. 
Mean. 
Calculation. 
Carbon . 
89-2 
89-5 
89-5 
89-4 
Q20 
120 89-6 
Hydrogen 
10-5 
10-4 
10-4 
10-4 
Hh 
14 10-4 
134 100-0 
The above numbers completely correspond with the formula 
C20 
which is eridently that of cymole. Moreover the density of the fluid, 0-8664 at 20°, 
was almost the same as that given by Gerhaedt, namely, 0-8610 at 14°. 
I could have wished to give equations expressive of the entire decompositions which 
take place, and it would be easy to do so were I to disregard, or consider as merely 
accidental, the substances formed at the same time. When the brominized o-il is 
distilled, before or after treatment with alcoholic potash, nearly fifty per cent, of loss is 
incuri’ed. The retort contains a black carbonaceous mass, occupying two-thirds of its 
capacity. A similar phenomenon occurs in the treatment with sodium ; and at the 
same time, as I have said, a certain portion of caoutchine or turpentine, as the case may 
be, is regenerated. 
The yellow oil of high boiling-point previously alluded to, exists in very small quan- 
tity among the products formed by the action of sodium on brominized caoutchine ; 
probably not more than one-tenth of the distillate boils above 200° C., whereas the 
yellow oil boils only a little below 300° C. The quantity in my possession was far too 
small to allow of a determination of this point. In composition, however, it agreed 
with that of cymole. 
0-2224 grm. gave 0-7312 carbonic acid and 0-2022 water. 
Experiment. Calculation. 
Carbon . . 
, 89-7 
C20 
120 
89-6 
Hydrogen . 
10-1 
H'^ 
14 
10-4 
134 
100-0 
* Since writing the above, I have compared the cymole from caoutchine, and that from oil of turpentine, 
with a specimen of the same hydrocarbon, prepared with great care from oil of cumin by niy friend Mr, 
Chuech ; the odom? in each case was absolutely identical. 
2 L 2 
