325 
having been washed with distilled water, and dried at 212' Wedg- 
wood, weighed 1.3 grain. Upon projecting a small portion in colour- 
less sulphuric acid, nearly boiling, sulphureous gas was evolved, and 
the acid slightly blackened. On projecting of another portion in 
boiling nitrate of pot-ash, gas was liberated, without sparks, or scin- 
tillation. There are undoubtedly, Mr. Pepys remarks, difficulties in 
ascertaining from what source the carbon may have been derived ; 
the purest and most caustic alkali obtaining carbon in its treatment 
with alcohol, which mechanical means alone have yet been able to 
separate. Willing to obtain some more information with respect to 
these volatile matters, which might have escaped at 212” Wedgwood, 
I made the following experiment. 
One hundred and eighty grains of jasperized wood, taken from a 
part where the ligneous form was most apparent, were placed in a 
glass retort, over the naked coals. When the bottom of the retort 
became red hot, a vapour became visible in its upper part, and the 
neck became discoloured by a light brown tinge, several small drops 
of water collecting in it at the same time. The bottom of the retort 
beginning now to run, the process was stopped. Upon examination, 
when the vessels were cold, the matter which had coloured the 
neck of the retort, appeared to be in too small a quantity, to de- 
termine its nature with any approach to precision. Tlie water had 
very little taste : but both the retort and receiver yielded a very 
pungent, empyreumatic bituminous smell ; which the latter retained 
for several days. This experiment, though imperfectly performed, 
seems to be sufficient to establish the fact, that some remains of 
bituminized vegetable matter were still present in the jasperized 
wood. 
However great is the variety in which jasper is presented to our 
observation, there is hardly any appearance which it bears, which is 
not exactly borne by fossil wood. In one specimen of fossil wood, 
now before me, the fibrous texture of the wood is evident, whilst it 
