128 Dr Grecory on the Composition of 
The naphtha examined by Saussure, then, that analyzed by 
Dr Tomson, that which may be extracted from the Rangoon 
petroleum, and that now sold in Paris, all agree in yielding a li- 
quid of sp. gr. 0.753 to .765; while that of oil of turpentine is 
0.830, and has never been stated lower than 790. Moreover, Dr 
Tuomson’s Persian naphtha, that of Rangoon, and the commer- 
cial naphtha from Paris, all possess, in a considerable degree, the 
characteristic odour of eupione. If we consider that the specific 
gravity of pure eupione is 655, we shall not be surprised that its 
odour is somewhat disguised, when it is so impure as to have the 
sp. gr. 750. But we have other means of distinguishing between 
eupione and oil of turpentine. The first is the action of nitric 
acid. The violent decomposition produced by it in oil of tur- 
pentine is well known. I have tried Persian, Rangoon, and com- 
mercial naphtha with the very strongest fuming nitric acid, such 
as set fire to turpentine, but there was no action except at a high 
temperature, when a brown colour was produced. In fact, the 
Rangoon naphtha, during its purification, was distilled with sul- 
phurie acid and nitre without change. The next test was the 
action of iodine, which produces a slight explosion when intro- 
duced into oil of turpentine. In the three varieties of naphtha 
just mentioned, there was scarcely any action beyond simple so- 
lution, and, in all, the solution had a rich violet colour, which is 
the colour of a solution of iodine in eupione. I am induced to 
suspect that a small quantity of oil of turpentine may be present, 
from the slight action manifested by nitric acid, and even by 
iodine, at a high temperature. But the presence of oil of tur- 
pentine is to be looked for in these liquids, if we consider them 
the products of the destructive distillation of Coniferze, since the 
first effect of heat would be to expel the oil of turpentine, which 
would afterwards mix with the products of the true destructive 
distillation. Even admitting, therefore, that these varieties of 
naphtha contain oil of turpentine, still I conceive we must be sa- 
tisfied that it is not a chief ingredient, far less, as in the oils ex- 
