158 Miscellaneous Intelligence. 



titanium from other substances, in minerals containing it, and 

 which he thinks requisite to its correct estimation. 



1. The mineral is to be finely pulverised, heated with two parts 

 of potash, the crucible being taken from the fire when incan- 

 descent ; the produce is to be diffused through water, put on to a 

 filter, and washed, until test paper ceases to be affected. The 

 washings are slightly supersaturated, evaporated to a moist solid 

 state, diffused through water, and put on to a filter : the silica 

 separated when washed and dried, is treated with oxalic or muri- 

 atic acid, and the washings added to the former washings ; infusion 

 ©f galls is then added, and the solution made slightly alkaline 

 and concentrated ; if the characteristic brown red tint of tita- 

 nium appears, the solution is set aside, to be subjected to further 

 examination. 



2. The residue, insoluble in potash, is boiled with a mixture of 

 one muriatic acid and six or eight of water ; if a larger quantity of 

 insoluble matter than was expected appears, it is treated with 

 potash, as before. The acid solutions are saturated with an 

 alkaline subcarbonate, and after having separated the precipitate, 

 the liquid is examined, as was that in section one, and if it contains 

 titanium, is mixed with it. 



3. The precipitate formed in the last section, is exposed to the 

 action of potassa, and as the titanium is partly dissolved in the 

 alkali with the alumina, and partly thrown down again with it, by 

 muriate of ammonia, sulphate of ammonia is used instead, which 

 is found to precipitate only alumina ; when this earth has been re- 

 ceived and washed on a filter, the liquids are evaporated to a 

 moist saline state, and by solution in water, such portion of silica 

 separated from it as was previously dissolved. Infusion of galls 

 is added to the washings, all of which are added to the preceding 

 washings of 1 and 2. 



4. As the titanium does not dissolve in potash so readily as the 

 alumina which accompanies it, the insoluble portion preserves a 

 gelatinous appearance ; to separate the titanium, the residue is 

 dissolved in muriatic acid, the silica removed by a filter, the iron 

 separated by ferroprussiate of potash, the liquid saturated by 

 an alkaline subcarbonate, and boiled. The precipitate which 

 fonns, is white, bulky, and resembles alumina in appearance ; it 

 may be composed of oxide of titanium, magnesia, and lime ; a 

 strong heat renders the first insoluble in acids, and consequently, 

 the earths may be removed by digestion of the whole for some 

 hours in weak acid, as distilled vinegar. The insoluble portions 

 are to be separated on a filter, the liquid treated with ammonia 

 for the magnesia, and with oxalate of ammonia for the lime ; the 

 operation has been well performed, if infusion of galls produces no 

 effect in the remaining solution. 



5. As titanium forms double salts with all the acids, and as its 



