TITANIUM. 83 



with an excess of ammonia. Flocks fell down, 

 which consisted of titanic acid and peroxide of 

 iron, still in combination with each other. These 

 flocks were washed, and pat into a flask while 

 still moist, and hydrosulphuret of ammonia 

 poured over them. In this situation the mixture 

 was left for some time. The iron was gradually 

 converted into a sulphuret, while the titanium 

 still continued in the state of titanic acid. The 

 hydrosulphuret of ammonia being washed off, 

 and the residuum digested in muriatic acid, the 

 iron was dissolved, and the titanic acid left be- 

 hind in a state of purity. 



Titanic acid, thus obtained, has a fine white Properties 

 colour. When heated to redness it becomes add. n 

 yellow, but when cold the original white colour 

 again appears. After exposure to a red heat, it 

 is insoluble in acids ; but when precipitated 

 from muriatic acid by heat it continues slightly 

 soluble in that acid. When precipitated titanic 

 acid is digested in water, that liquid passes 

 milky through the thickest paper, and the acid 

 cannot be collected on the filter ; but this pro- 

 perty is destroyed by an acid, or an alkali, or 

 even a neutral salt. When titanic acid is fused 

 with potash, and dissolved in muriatic acid, and 

 the solution evaporated, the titanic acid often 

 gelatinizes, but the jelly is never so stiff as that 

 of silica. When titanic acid, precipitated by 



heat, is dried by a gentle heat, the surface is 



F 2 



