360 Elements of Mineralogy. 



u. This acid is itfelf foluble in the vi- 

 triolic acid with the affiftance of heat, and 

 the folution is blue when cold, though co- 

 lourlefs while hot ; it is alfo foluble in the 

 marine acid, but not in the nitrous. 



12. Molybdenous tartar and ammoniac 

 precipitate all metals from their folutions by a 

 double affinity. Gold, fublimate corrofive, 

 zinc and manganefe, are precipitated <wkite -, 

 iron or tin from the marine acid brown ; co- 

 balt red ; copper blue. 



13. Alum and calcareous earth white* 

 Scheek Mem. Stock> 1778. 



14. This acid has been lately reduced by 

 Mr. Hielm^ but the properties of the regu- 

 lus thus obtained are not yet publifhed. 



CHAP. XVIII. 



Of the Tungftenic Acid. 



Though this acid, and the manner of ob- 

 taining it have been already mentioned, p. 38, 

 yet as it is of a metallic nature, a few of its 

 diftinguifhing properties may properly be in- 

 ferted here. 



i. Its folution in water reddens that of 



litmus ; 



