Titanium from Minerals. 201 



lowed in the analysis of a mineral with a base of titanium, and 

 then relate some of the important results with which it has 

 furnished me. 



1. I treat the porpiiyrised mineral with two parts of potash: 

 withdrawing the vessel from the fire when the mass is at a 

 white heat, I mix the product in water, throw it on a filtre, and 

 wash the insoluble residuum till the liquid no longer acts on 

 test paper. To separate from the washings the small portion 

 of titanium which is dissolved with the silica, I slightly super- 

 saturate them, evaporate them to a humid saline consistence 

 iji a porcelain vessel, moisten the saline product in water, and 

 receive it on a filtre, where the silica becomes deposited ; 

 then, after having washed and dried it, I expose it to the ac- 

 tion of diluted oxalic or hydrochloric acid, to separate from 

 it the titanium or any other substance which might be depo- 

 sited with it. I next add the liquid from which I have se- 

 parated the silica to the acid solution with which it had been 

 acted upon ; I treat them with the infusion of galls, render 

 them slightly alkaline, concentrate them ; and if tliey take the 

 red-brown colour which characterizes titanium, I put them by, 

 to examine at the end of the operations. 



2. I submit the insoluble residuum in the potash to the ac- 

 tion of hydrochloric acid, diluted with six or eight parts of 

 water, with the aid of boiling: if a greater quantity -of inso- 

 luble substance remains than would be expected, I treat it a 

 second time with potash, and pursue with it the operations 

 above stated. I then saturate the acid solutions with an alka- 

 line subcarbonate ; and after having separated the precipitate 

 from it, I evaporate the liquid to a moist saline consistence, 

 proceed widi the deposit which may be formed there by the 

 solution of the product in water, as with that of § 1 ; and finding 

 the action of the infusion of galls on the washings as has been 

 mentioned, I add them to the former solutions of the same na- 

 ture, if it indicates the presence of titanium. 



3. I expose the precipitate formed in the acid solution to 

 the action of potash ; and us the titanium dissolves wholly or 

 in part with die alumine, and the hydrochlorate of ammonia, 

 in leaving a portion of dissolved titanium, precipitates a great 

 part of it with the alumine,— to avoid this cause of error, which 

 was formerly unknown, I use in its place sulphate of ammonia, 

 in which I have discovered the property of precipitating the 

 alumine only; and when I have received and washed this 

 earth on a filtre, I evaporate the liquids to a humid saline 

 consistence ; I separate, by solution of the product in water, 

 some little of die silica which was dissolved in it ; I throw some 



Vol. 65. No. 323. March 182.5. C c infusion 



