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amined was twenty ounces. Having elutriated the 

 mafs fufficiently with hot water, filtered and eva- 

 porated the foiution till a pellicle was forming on 

 the furfacc, I fct it by to Ihoot ; when it had flood 

 a fufficient time, I found plenty of the moft beau- 

 tiful prifmatic cryftals depofited. But I was not a 

 little furprized to find that thefe when committed 

 to the fire would not deflagrate; whereupon, tafting 

 this fubflance, I concluded it to be not falt-petre, 

 but that fpecies of fait which is termed by chemifts 

 Sal Mirabile^ or Glauber's Salt. The quantity of 

 faline matter obtained from the whole foiution 

 weighed fix ounces. 



On farther confideration, it does not feem diffi- 

 cult to account for the produ(flion of one of the 

 conftituent parts of Glauber's fait in the place where 

 this was found. It is well known to chemifts 

 that the acid of fulphur is the fame as the acid of 

 vitriol, and that this acid is one of the efl'ential 

 parts of Glauber's fait. Pit-coal contains a large 

 proportion of fulphur. The acid, I apprehend, is 

 fublimed in the fire, and meeting in its afcent with 

 the fteam which is conftantly evaporating from 

 the furnace, becomes condenfed, is precipitated, 

 and imbibed by the abforbent matter of which the 

 walls arc compofed. To account for the other 

 conftituent part does not appear to me quite fo 



eafy. 



