Re-action of Sulphuric Acid on Camphor. 433 
portion of the hydrogen and of the carbon may combine 
with the nitric acid, and form a compound, fusible by heat, 
and partly soluble in water, and which possesses some of 
the properties of resins; and that, consequently, .we are 
perbaps too hasty in regarding pit-coal, which furnishes 
similar products when treated with nitric acid, as being 
formed of @ resin similar to that of recent vegetables, and 
Gf a coaly substance: this opinion may be. true, but the 
facts brought in support of it are not sufficient to. prove it,., 
-4. They demonstrate, that, if the manner in which the 
coaly residuum 1s acted upon by the nitric acid indicates 
some analogy between this compound and pit-coal, yet the 
facts related above do not permit us, at least at present, 
to regard them as having.one and the same origin. Indeed 
when the sulphuric acid acts upon the camphor, (and what , 
takes place with that must take place with other vegetable 
substances,) it unites with the uncombined carbonated sub- 
stance: consequently, af pit-coal, was formed.in the, same 
manner, we must find sulphuric acid in it; besides, if we 
recollect that M. Proust, although he suspected there was 
a combination of sulphur with carbon in, pit-coal, could 
not discover the least trace of sulphurous acid in that sub- 
stance, when depriyed of its sulphate of iron, we shall con- 
sider the hypothesis of the formation of pit-coal, by means 
of the sulphuric acid, as totally inadmissible. 
I wished to determine the quantity of sulphuric acid con- 
tained in 100 parts of coaly residuum. For this purpose; 
1 fused nitrate of potass in a crucible of platina, and pro- 
jected into it the residuum in sinall quantities: although I 
bad taken every necessary precaution that nothing should 
be lost, I always found that.a small portion of the matter 
escaped combustion, and that it was carried out of the 
crucible by the gas, which was disengaged with impetuo- 
sity: the quantities of sulphuric acid here given, must not, 
therefore, be taken as completely accurate, In one experi- 
ment, I obtained a precipitate of sulphate of barytes, which 
indicated 5 parts of sulphuric acid; and, in another, a pre- 
cipitate, which indicated 6 parts in the 100 of the coaly ree 
siduum. 
One cireumstance I must not omit to mention,—that I 
discovered traces of the existence of lime and oxide of iron 
in the camphor I employed in my experiments, and which 
had been twice sublimed. 
. Examination of the Washings. 
These were, as I have mentioned, diyided into two par- 
Vol. 37. No, 158, June 1811. Ee cels 5 
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