138 



tJLTRAMJLRlNE, 



geilating end completely deprives it of colour^ buf ih& 

 hydrogenating extremity occasions no change. 



©xigengas; c. Oxigen gas changes the colour of ultramarine ex* 



posed to a red heat, causing it to assume a dirty green 

 hue, with an augmentation of weight of one per cent., 

 OM'ing probably to the formation of sulphurous acid 

 "vvhich adheres to it. 



hidfogen gas; 7. Ilidrogen gas in the same circumstances changes the 

 colour of ultramarine completely, imparts to it a reddish 

 colour, and takes from it sulphur. There does not ap- 

 pear to be any water formed, but there is a loss of weight 

 somewhat exceeding that of the sulphur. 



sulphur; g. Sulphur in fusion does not rob it of colour, and 



after being driven oft' by volatilization, leaves the ultra* 

 marine as beautiful as before. 



jHilphuratedhi- 9. Liquid sulphurated hidrogen has no action upDn it, 



drogen; jq^ q^- jime-water the same may be said. 



Iimewater; •' 



water of bary- H. Water of barytes, assisted by heat, deprives it of 



*^> colour, and is afterward found to contain silex and 



alumine. 



mineral acidsj jg. The sulphuric, nitric, muriatic, and oxigenated 

 tfitiriatic acids presently deprive ultramarine of its colour. 

 The first three in a concentrated state form with it a very 

 thick jelly, the fourth dissolves it almost entirely. 



If the sulphuric and muriatic acids be diluted with 

 water, sulphurated hidrogen is evolved. The action of 

 nitfic acid produces nitrous gas and sulphuric acid. 



acetous acid ; 13. The acetous acid acts upon it in a similar manner, 

 but more weakly. 



alcalij; 14, Potash and soda in solution heated with ultrama- 



rine diminish its weight, and arc found to contain alumine. 

 They do not alter its colour. 



pure potash; If "pure potash be heated strongly on ultramarine, its 



colour is destroyed, the result of the fusion is redish, and 

 comports itself nearly as if the ultramarine were an 

 argil, or a stone comj)osed of silex and alumine. 



ammonia; 15, Ammonia has no action upon it. 



©11. " 16. If oil be heated with ultraraine, the weight of the 



latter is diminished after being washed in an alcaline solu- 

 tion. 



Difficult of 17. The analysis of ultramarine appeared to us more 



""^■J""- . difficult 



