106 Experiments rin a Substance which possessed 



time the sand-bath had verv seldom been heated^ but the 

 vessel was occasionally shaken. 



At the end of the period above mentioned, six ounces of 

 boiling water were added, and, the whole being poured upon 

 a filter was repeatedly washed, and was afterwards dried on 

 a sand-bath in a heat not much exceeding 300". 



The saudusl appeared to be reduced to a granulated coal, 

 partlv pulverulent, and partly clotted : the whole weighed 

 210 grains. 



103 grains of this coal were put into a platina crucible, 

 and were exposed to a red heat under a muffle. At the same 

 time, an equal quantity of charcoal, made from the same oak 

 sawdust, was placed in another vessel bv 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 sulphate, which was probablv sulphate of potash. 



On the contrary, the coal fornK'd bv the humid wav 

 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 two grains. These 

 did not yield the smallest vestige of alkali, and the only sa- 

 line substance which could be obtained was a very small por- 

 tion (jf sulphate of potash, which did not amount to more 

 than l-5Lh 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 bcirun, 

 1 also put 480 grains of the oak sawdust into another ma- 

 trass, and, having added four ounces of conmion jruiriatic 

 acid, the whole v.'as 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 exceedintr 

 300". The sawdust then had the appearance of a brownish- 

 black mass, on which abt)ut a pint of boiling distilled water 

 was poured ; the whole was decanted into a filter, was re- 

 peatedly 



