Mineralogy. t^ 



sect, cxxxix. 



B. Borax. 



This is a peculiar alcaline fait, which is 

 fuppofed to belong to the mineral kingdom^ 

 ana cannot be otherwife defcribed, than that 

 it is either fome unknown alcaji, united 

 with an earth, which is diflbluble in water* 

 and vitrefcible •, or an alcaline fait, which is 

 fixed in the fire, and melts to a glafs, which 

 glafs is afterwards difibluble in water. 



Many experiments have been made with 

 it, in order to difcover its origin and conftitu- 

 ent parts, and therefore it is amply treated 

 of in chemical books ; and its following qua- 

 lities are to be obferved. 



1. It (wells and froths in the fire, as long as 

 any humidity remains in it, but melts af- 

 terwards very eafily to a tranfpareht glals, 

 which, as it has no attraction to the phlo- 

 gifton, keeps itfelf in the form of a pearl 

 on the charcoal, when melted with the 

 blowpipe. 



2. It changes the fyrup of violets into green ; 

 and precipitates the folution of allum, and 

 that of metals, made with acids. 



?, It unites with mineral acids to a neutral 

 fair, which moots into very fine and fubtile 

 hair-like criftals, and is called fal feclativum. 

 In a certain ccmpofition it is volatile •, and 

 mixed with litmus^ or fucc its helibtropi, and 

 the fyrup of violets, it difcovers marks 

 both of an alcali and an acid. 



4. When it has been united with the vitriolic 

 acid and a phloglfbon, no bejtar fulphziris is 

 produced. 



L 5, After 



