Gold. 235 



g. This and fueh like ores, may be eflfayed 

 by diflblving them in about 12 times their 

 weight of dilute nitrous acid, gradually added, 

 and a heat of about 1 20 degrees ; this takes 

 up the foluble part, and leaves the gold un- 

 touched with the infoluble matrix, from which 

 it may be feparated either by lotion, or by 

 aqua regia,* from which it is precipitable as 

 above. The fulphur floats for the moft part 

 on the folution from which it mould be fe- 

 parated by filtration. The folution may con- 

 tain iron, copper, manganefe, calcareous 

 Earth,, or argill j if it be evaporated to 

 drynefs, and the refiduum heated to rednefs 

 for half an hour, volatil alkali will extract 

 the copper ; the dephlogifticated nitrous 

 acid, the Earths ; the acetous, the manga- 

 aefe ; and the marine, the calx of iron. 



i o Gold may alfo be feparated from py- 

 jites after torrefadion, by aqua regia, Mon. 

 Mineral. 277. 



1 1 . Pyrites containing gold, is alfo found in 

 Siwijjerland and Hungary, that found in Hun- 

 gary, contains 5 ounces of gold per quintal, 

 Mon. Expo/itions des Mhies^ p. 47, the gold 

 mines of Norway, are of the fame nature as 

 thofe of Addfors, 2 Jars. 



12. la 



