Re-action of Sulphuric Acid on Camphor. 429 
pears to me to be of great importance, as I shall show here- 
after, 
3. Action of Potass. 
Having in a former experiment observed that a mixture 
of ten parts of saturated carbonated potass with two parts 
of the coaly residuum exhibited scarcely the slightest traces 
of sulphuric acid, I wished to know if pure potass would have 
any greater effect. For this purpose, I boiled for two hours 
two grammes of the coaly residuum in water containing six 
grammes of pure potass dissolved in it. I lettthe substances 
to peact on each other for the space of 12 hours afterwards, 
I then poured off the water and filtered it. A brown liquid 
ran through, and there remained upon the paper a black 
matter, which was washed in boiling water until the water 
was no longer coloured, and no longer gave any precipitate 
with water of barytes. The ‘filtered alkaline solution was 
saturated with nitric acid*, there was a slight effervescence, 
a precipitation of brown floccules took place, and the liquid 
jost its colour. This liquor being again filtered, there was 
added to it a solution of barytes; at first there was not any 
precipitation, but in about two hours it threw down a very 
small particle of sulphate. Hence it follows, that the po- 
tass subtracts from the coaly residuum but an infinitely 
small quantity of sulphuric acid. | 
The brown floccules, which had been precipitated from 
the alkaline liquor by means of the nitric acid, were washed, 
first in cold and afterwards in warm water: this last dis- 
solved a portion of them, and without doubt would have 
dissolved the whole, had it been in sufficient quantity. 
This solution was slightly acid: sulphuric, nitric, and mu- 
riatic acids caused a precipitation in it, probably by uniting 
with the matter it held in solution; barytes produced from 
it a precipitate soluble in hot nitric acid. I had too small 
a quantity of the brown floccules dissolved in potass to 
determine the nature of them, but T believe them to be 
composed of coaly residuum, nitric acid, anda small quan- 
tity of potass. 
Part of the coaly residaum which had not been dissolved 
in the alkali, being well washed and dried, gave out when 
heated in a glass vessel, 1. carbonic acid gas in great quan- 
tity; 2. sulphuretted hydrogen gas; 3. oxy-carburetted 
. hydrogen gas; 4. a coal which gave out a very stroug smell 
of sulphur when breathed upon. I supposed from this ire 
* An excess of acid is necessary to render the precipitation complete. It 
would appear that this excess enters into combination. 
cumstance 
