On the ammoniacal Liquor of Coal Gas. 265 
ents, and the quantity of ammonia it-contained. Having evapo- 
rated some of the clear ammoniacal liquor from the tar-tub to 
dryness, | was surprised to find so little crystallizable salt, and 
that enveloped in a black mass of carbonaceous and oily matter, 
highly impregnated with sulphuretted hydrogen. This not being 
at all satisfactory, I next proceeded to rid it of its sulphuretted 
hydrogen by oxidizing the sulphur. To this end I poured gently 
into some ammoniacal liquor some muriatic acid, which caused 
a blackish precipitate, and kept stirring the liquor as I added the 
acid: at length a strong effervescence took place, aud sulphuretted 
hydrogen was liberated. I kept adding acid till it caused to effer- 
vesce. This I presumed would at the same time neutralize the 
ammonia and form a muriate of it, or sal ammoniac. Having 
let it precipitate its black matter, which seems to be a compound 
of sulphur and carbon, [ resumed the evaporating of some of it ; 
when, to my surprise, after it had been over the lamp some time, 
it let fall another precipitate, which I collected and washed, and 
found it possessing a waxy nature, insoluble in water, but readily 
so in alcohol; imparting to it a reddish brown tint. When 
rubbed on the finger moistened with alcohol, it gave a permanent 
brown dye. The evaporation of the remaining portion of liquor 
was going on, when I was still more surprised to observe amongst 
the crystals forming at the edge of the evaporating basin, mi- 
nute globules of a beautiful red, or rather lake colour, floating 
smartly about, till at length by the heat at the edges they boiled, 
and seemed to undergo a partial decomposition, giving out a 
very peculiar aromatic smell, but still preserving their bright co- 
lour. 
After it was evaporated to dryness, I left it for a day or two, 
at intervals making experiments upon the remaining portion of 
liquor I had not submitted to heat. If into a test glass full of 
this a piece of linen be dipped, it will soon become red; but in- 
stantlv, if a solution of sub-carbonate of potash be dropped upon 
it, or if a few drops be added to the liquid in the test-glass, it 
turns of a reddish-brown hue, which partly deposits its colouring 
matter by standing. By this time the lake-coloured crystals were 
all deliquesced, and the beautiful colouring matter was floating 
on the top like oil. This I also collected. It will not unite with 
water, but readily so in alcohol. Besides the difference of co- 
lour, it possesses properties different from the brown deposit which 
at first took place: it permanently stains the fingers; has a pe- 
culiar astringent taste, not unlike tannin; but is not in the least 
altered by sulphate of iron. If a portion be pressed upon filter- 
ing paper, a colourless oi/ will spread all round it; or if a small 
bit be placed upon the tongue, after a minute or two an intense 
sensation of burning will be felt, just like that produced by any 
: of 
