MR. JOHNSTON ON THE CONSTITUTION OF THE RESINS. 
345 
The formula C 40 H 33 O 3 gives 
Per cent. 
40 Carbon = 3057'440 71 ‘62 
33 Hydrogen = 41T827 9*64 
8 Oxygen = 800*000 18*74 
4269*267 100- 
3. The resin in the state in which it had been analysed, as above, was boiled in 
water, which became slightly coloured, and acquired a bitter taste. 
It was then dried by prolonged heating at 212° Fahr., when 
5-93 grs. gave C = 15-97, and H = 5-34, or per cent., 
3 . 
Carbon 73’99 40 atoms. 
Hydrogen 10*00 33*1 atoms. 
Oxygen 16-01 7'05 atoms. 
100 
4. This remarkable disagreement with the previous results induced me to boil in 
repeated portions of water, a second quantity of the labdanum of commerce, and after 
drying, to digest it in alcohol. The water acquired a brownish colour, and an in- 
tensely bitter taste. A portion of the alcoholic solution was evaporated and heated, 
as before, in a thin film. 
8-385 grs. gave C = 22-205, and H = 7‘57 grs. 
5. Of the resin thus analysed (4.) the remainder was again boiled in water. The 
first portion of water was not coloured, but acquired a very bitter taste ; in the second 
portion employed, the taste was scarcely perceptible. Dried by heating for thirty-six 
hours at 180° Fahr., it was darker coloured than the resin first analysed, and when 
hot had a slight odour resembling ginger. 
7"01 grs. gave C — 18*56, and IT = 6 - 3 7 . 
These two results are almost identical, giving per cent., 
4. 
5. 
c 40 H33 0 7 , gives 
Carbon 73*24 
73-16 
73-38 
Hydrogen 10*00 
10-01 
9*88 
Oxygen 16*84 
16-83 
16*74 
100 
100 
100 
In the portion 3, therefore, the carbon is in excess to the amount of 0'6 per cent., 
either from an error of experiment, or from the presence of some impurity in the 
portion analysed, while the identity in constitution of the portions 4 and 5, shows 
either that the bitterness imparted to the water by boiling over specimen 4, was due 
to the solution of the resin itself, or that the quantity of the bitter substance it con- 
tained was too small to affect the results of analysis in any sensible degree. 
MDCCCXL. 2 Y 
