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cafy. Pit-coal however, it is certain, contains 

 fome fmall proportion of the foflil alkali, which, 

 though fixed in a lefs degree of heat, may be ren- 

 dered fomewhat volatile ; that is, may be expelled 

 to fome confiderable diftance by that intenfe degree 

 of heat which ufually melts the afhes, and converts 

 them into glafly fcoriEC. 



The water likewife which is drawn from coal- 

 mines is, I am told, fomewhat brackifli ; if (o^ 

 confequently it contains fea-falt. This water, after 

 being elevated, is conftantly dropping from the 

 furnace, and different parts of the engine, on the 

 walls and ground beneath; where, if it found the 

 condenfed vitriolic acid, which is more powerful 

 than the marine, the latter would be expelled, and 

 the former attaching itfelf to the alkali, their union 

 would produce the neutral fait in queftion. I am 

 not quite fatisfied with this fuppofition refpeding 

 the alkaline part of the compofition, as I cannot 

 conceive that even both fources from whence I 

 have fuppofed the alkali to proceed, could furnifh 

 any confiderable quantity. It is -a fad", however, 

 that a fait is produced in the fituation I have dc- 

 fcribed, which I take to be a true Glauber's fait. I 

 have fent you a fpecimen; and could wi(h to have 

 it examined by a perfon of more knowledge in 

 thcfe matters than I can pretend to, 



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