THE ALKAHEST OR UNIVERSAL SOLVENT 



(HE production of a universal solvent or alkahest 

 was one of the special problems of the alchemists 

 in their general search for the philosopher's 

 stone and the means of transmuting the so-called 

 inferior metals into gold and silver. Their idea of the 

 way in which it would aid them to attain these ends does 

 not seem to be very clearly stated in any work that I have 

 consulted ; probably they thought that a universal solvent 

 would wash away all impurities from common materials 

 and leave in absolute purity the higher substance, which 

 constituted the gold of the adepts. But whatever their 

 particular object may have been, it is well known that much 

 time and labor were expended in the fruitless search. 



The futility of such attempts was very well exposed by 

 the cynical sceptic, who asked them what kind of vessel 

 could they provide for holding such a liquid ? If its solvent 

 powers are such that it dissolves everything, it is very evi- 

 dent that it would dissolve the very material of the vessel 

 in which it must be placed. 



When hydrofluoric acid became a subject of investigation 

 it was thought that its characteristics approached, more 

 nearly than those of any other substance known, to those 

 of the universal solvent, and the very difficulty above sug- 

 gested, presented itself strongly to the chemists who ex- 

 perimented with it. Not only common metals but glass 

 and porcelain were acted upon by this wonderfully ener- 

 getic liquid and when attempts were made to isolate the 



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