370 MR SCHMIDL ON THE CONSTITUTION OF OIL OF CAJEPUT. 
could I then by any reagent or operation detect the presence of copper, as I did in 
the crude oil. 
The fact, however, that copper almost invariably is found in the crude com- 
mercial article, can only be accounted for, either by the use of a copper head in 
the distilling apparatus of the Indians, or by intentional adulteration employed 
in order to preserve the green colour of the oil, which it otherwise, as I have 
convinced myself, loses when in process of time oxidation takes place, in conse- 
quence of which a reddish brown colour is produced, which is said to make the 
article, for medicinal purposes, less saleable. 
The Specific Gravity of the Crude Oil at 10° C.=0°926.—It does not solidify 
at — 25° C.; its taste is pungent and aromatic; its smell only pleasant when 
diluted, but very disagreeable when concentrated ; it is soluble in all proportions 
in alcohol and ether. When submitted to distillation, it becomes turbid at 120° 
C., and acquires a yellowish brown colour; at 175° C., it commences to distil 
over, and before the thermometer indicates 178°, nearly two-thirds of the oil 
have passed over, the fluid collected being limpid and perfectly colourless ; from 
178° to 250° C. the mercury rises gradually, without showing any distinct boiling 
points. The fluid passing over between this long interval changes gradually — 
from a pale yellowish colour into darker shades, approaching always more and 
more to green, until at last the fraction between 240° to 250° C. becomes of a dark 
untransparent green colour. 
At 265° C. the retort is almost dry, retaining some metallic copper mixed with 
carbonaceous and resinous matter, which, when treated with ether, imparts to this — 
reagent a green colour, and on evaporation of the latter a green resin is left be- — 
hind, which is soluble in the rectified fraction (boiling at 175° C.), and thereby 
able to restore the coloured appearance of the original oil. 
Whether the fractions beyond 178° C. be special and pre-existing constituents 
of the crude oil, or mere products of decomposition, and therefore of changeable — 
character, I am as yet not able to state, since the results of operations performed 
with them are either contradictory as to this effect, or not yet sufficient to coun- — 
tenance the one or the other of these opinions; but still, in the course of time, 
and in a second paper, I hope I will be able to give some satisfactory accounts 
about them. | 
Most of my operations are therefore confined to the first large fraction, boiling 
at 175° to 178° C. ; in particular cases, however, which I shall endeavour to specify, 
the crude oil has been employed. 
I. BIHYDRATE OF CAJPUTENE, C,, H,,+2HO. 
I commenced my experiments by agitating the rectified fraction with bisul-— 
phate of soda, by means of which I satisfied myself of the absence of aldehydes 
and other bodies, capable of combining with that substance. And as, from the 

