134* Mr. Hatchett’s Experiments on a Substance, 
time, an equal quantity of charcoal made from the same oak 
sawdust, was placed in another vessel by the side of the 
former. 
The charcoal was speedily consumed, and left some 
brownish-white ashes, which as usual, afforded alkali, with a 
trace of a sulphate, which was probably sulphate of potash. 
On the contrary, the coal formed by the humid way, 
burned without flame, similar to the Kilkenny coal, and 
others which do not contain bitumen. It was very slowly 
consumed, like the mineral coals above mentioned, and left 
some pale red ashes, which weighed 2 grains. These ashes 
did not yield the smallest vestige of alkali , and the only saline 
substance which could be obtained, was a very small portion 
of sulphate of potash, which did not amount to more than -§• 
of a grain ; and it is probable, that had the coal been more 
copiously washed, even this small portion of the neutral salt 
would not have been obtained. 
2. 
At the time when the preceding experiment was began, I 
also put 480 grains of the oak sawdust into another matrass, 
and having added four ounces of common muriatic acid, the 
whole was suffered to remain during the period which has 
been mentioned. 
At the end of the four months, the remainder of the acid 
was for the greater part driven off by heat not exceeding 
300°. The sawdust then had the appearance of a brownish- 
black mass, on which about a pint of boiling distilled water 
was poured ; the whole was decanted into a filter, was re- 
peatedly washed, and was afterwards dried without heat. 
The sawdust then appeared, as I have observed, brownish- 
