OF ARTS AND SCIENCES. 447 



hydrofluoric acids to recover titanium which may be with the silica. 

 It is better in most cases to effect the decomposition of a sihcate by 

 means of one of the fluoride methods, or by fusion m an alkahne 

 carbonate, the melt in the latter case being acidifled with hydrochloric 

 acid, and the residue after evaporation and filtration worked over with 

 sulphuric and hydrofluoric acids for the recovery of that portion of the 

 titanium which remains insoluble after the evaporation. 



