122 Prof. Hiinefeld on the Tituniferons 



A portion of the slag was digested in aqua regia : the greater 

 part of it was dissolved, with evolution of sulphuretted hydro- 

 gen gas, whilst a considerable number of the small cubes of 

 titanium remained undissolved, having a perfect metallic lustre. 

 But besides these, there remained in the residuum a blackish 

 powder, containing grains and minute laminae, nearly of the 

 colour of silver, and having a metallic lustre, to which I shall 

 return in the sequel. Another portion of the slag was ignited 

 with nitre, in order to oxidate the titanium. The melted mass 

 dissolved in water gave a beautiful green solution, which, when 

 exposed to the air, soon assumed first a deep red, and then 

 a dark violet colour, and at last lost all colour *, whilst por- 

 tions of the protoxides of manganese and iron were deposited. 

 Subsequently, this deposit (marked a) and the sides of the 

 vessel became covered with fine crystalline iridescent laminae 

 and needles, probably titanate of potash precipitated by the 

 substances having attracted carbonic acid from the air. 



The residuum of the dissolved mass in the porcelain crucible 

 was washed and dried, by which it assumed the colour of iron- 

 rust. It was partly dissolved in muriatic acid, and thereby 

 gave a solution of iron, and left a blackish powder (b). The 

 filtered strongly alkaline re-acting liquid was evaporated, and 

 mixed with nitric acid (c). After standing somewhat longer, 

 il gave crystals of nitre, and then others of an indistinct form. 

 They were mostly white, somewhat opalescent, not easily solu- 

 ble grains of salt, cracking and decrepitating between the 

 teeth, and which, with salt of phosphorus, were melted before 

 the blowpipe into a clear bead, which within the flame re- 

 ceived no colour, either by itself or mixed with tin. The so- 

 lution was rendered somewhat turbid by caustic ammonia, and 

 white flakes were deposited. Boiled and dissolved with pot- 

 ash, and acidulated with muriatic acid, infusion of galls pre- 

 cipitated it of a dark yellow ; but hydrosulphuret of potash and 

 ferroprussiate of iron gave no precipitate ; which leads me to 

 suppose that those grains of salt were tantalate of potash. 



The fluid c had the following properties. With an alcoholic 

 infusion of galls, a yellowish-orange precipitate was formed, 

 which was dissolved on being heated ; and when it was con- 

 centrated, it gave a brown liquid, which remained clear on 



shown that the iron between the laminae of the cubes of pure titanium had 

 been mechanically interposed ; whence (like Wollaston) he also explains its 

 magnetism. 



* The cracks of the crucible contained a beautiful orange-red efflorescence 

 in needles, which were not examined. Were they manganesate of potash, 

 or sulphuret of titanium with sulphuret of potassium ? (Vid. Berz. Jahresber. 

 v. 134.) 



cooling. 



