MR. JOHNSTON ON THE CONSTITUTION OF THE RESINS. 
382 
that the state of our knowledge does not justify me as yet in forming more than a 
conjecture on the subject, yet at present I am inclined to regard the former opinion 
as much the more probable. In future papers, I hope to be able to place the question 
in a more satisfactory point of view, by the aid of other experimental researches, which 
I shall then have had an opportunity of bringing before the Society. 
In favour of the view of the constitution of the fragrant resins* above preferred, I 
would direct attention to the researches of Fremy, into the constitution of the balsams 
of Peru and Tolu-f-, in which he has detected an oily liquid (cinnameine = C 54 H 26 
0 8 ), convertible by the action of caustic potash into cinnamic acid = C 18 H 8 0 4 , and 
by chlorine, among other products, into chloride of benzyle, which water, as is well 
known, converts into benzoic acid. This action of potash on cinnameine he com- 
pares to that of the same base on oleine; and he considers it highly probable that the 
resin of benzoin, while in the balsamic state, contains an oily fluid, which by potash is 
convertible into benzoic acid. 
Fremy has also analysed the resin of benzoin in conjunction with those extracted 
by him from the balsams of Peru and Tolu, and that which is obtained by the action 
of sulphuric acid on cinnameine. 
His comparative results are as follow : — 
From balsam of Peru. 
From balsam of Tolu. 
From cinnameine. 
Resin of benzoin. 
Carbon 71 '82 
70-8 
71-9 
71-2 
Hydrogen 6 '78 
6T 
65 
65 
Oxygen 2T40 
23" 1 
21T 
22-3 
100 
100 
100 
100 
The several resins he concludes to be identical, and represents them by the formula 
C 54 H 30 0 12 , which nearly coincides with our formula C 40 H 22 0 9 , and gives carbon 
7 2 ‘ 4 , hydrogen 6’5, and oxygen 2 IT per cent. 
The above results, however, are too discordant to justify the conclusion that the 
resins are identical. Besides, he only gives one analysis of each resin, and describes 
them, in consequence of the instability of the compounds, only as tolerable approxi- 
mations^. That such is the case, indeed, is evident from his adoption of a common 
formula, which requires four-tenths (0*4) per cent, more hydrogen than was ob- 
tained by analysis in one of his experiments. In regard to his analysis of the resin of 
benzoin, it approaches nearest to No. 1. of the series given in the present paper, and 
may be considered in so far to confirm the statements I have had occasion to make, 
in regard to the slight circumstances by which the constitution of the resin may be 
made to vary, and the difficulty of admitting the opinion that the benzoic acid exists 
in it ready formed. 
The portion analysed by Fremy gave only 65 per cent, of hydrogen, and could not 
* Those represented by the formula C 40 H 24 + O y . 
f Annales de Chimie et de Physique, LXX. p. 180. 
J See his memoir, p. 204. 
