[ S5 1 ] 
Coal, incruflcd over with a white Salt, that appears 
in feparate Spots here and there in it. 
2. It has a ftrong fetid fulphureous Smell and 
Tafte, as well as a bitter and lixivial Tafte, which 
is rather more pungent than other common lixivial 
Salts. 
3. A Lixivium of it is of a dark -green Colour, 
With a very fetid fulphureous Smell, and bitter ful- 
phureous Talk, fomewhat like Gunpowder, as well 
as fharp and pungent like a limple Lixivium. 
4. Altho’ it is as hard as a Stone, when kept in 
a clofe Place, or in large Quantities together in a 
Hogfhead; yet, when laid in the open Air, it turns 
foft, and fome Pieces of it run per deiiquium 5 
whilft mod other kinds of Pot-afh only turn friable,, 
and crumble in the open Air. 
y. It readily diflolves in warm Water, but leaves 
a large Sediment of a blackifh grey Co'our like 
Afhes, which is in a fine foft Powder, without any 
Dirt or Coals in it, that are to be obferved in mod 
other kinds of Pot-afh. 
6. As it is dilfolving in Water, I have feum tried 
off from fome Lumps of it a dark-purple bituminous 
Subfiancc, like ‘Petroleum or Tar, which readily 
diflolved in the Lixivium. 
7. This, or any other true Pot-afh, or a Lixivium 
made of them, will prelentiy tinge Silver ot a dark- 
purple Colour, difficult to rub off* whilft a mere 
lixivial Salt has no fuch Eifecf. 
8. Pieces of this Pot-afh boiling in Water make 
a conftant Expiofion like Gunpowder 5 which was 
fo ftrong as not only to throw the Water to fome 
Height, but to lift up and alntoft overfet a ftone Cup 
in 
