335 



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 

 scintillation. There are undoubtedly, Mr. Pepys remarks, difficul- 

 ties 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, w"hich 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 examina- 

 tion, 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. The 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 



