Professor Berzelius on Thorina, 91 



The hydrate of thorina is insohible in caustic alkalies. On 

 the other hand, both the hydrate, the carbonate, and the suh^ 

 salts dissolve with ease in the carbonated alkalies, and in car* 

 bonate of ammonia. Very little is dissolved by the alkali, if 

 the solution is much diluted ; but they dissolve abundantly 

 and with ease if the solution be concentrated. If a solution 

 of thorina, in carbonate of ammonia, be put into a flask and 

 heated to + 50 (Celsius = 122 Fahrenheit) or thereabout, the 

 liquid becomes turbid, and much thorina is thrown down, which 

 is again completely taken up when the solution is allowed to 

 cool. The addition of caustic ammonia does not precipitate 

 the thorina ; and if, previous to the addition of ammonia, the 

 liquor were muddy, from the commencement of precipitation, 

 the ammonia restores its transparency. 



If thorina be heated to redness with a caustic or carbonated 

 alkali, it does not fuse with it, but becomes insoluble in muriatic 

 and nitric acids, which take up only the foreign matters with 

 which it may be contaminated, and which, previous to this 

 heating with alkali, could not be removed by acids. It separates 

 in the form of a white milk-like mass, which, in washings 

 passes through the filter, like titanic acid ; an effect, however, 

 which may be prevented by mixing muriatic acid or sal ammo- 

 niac with the washing water. 



Thorina, by heating to redness, becomes hard, and is after- 

 wards difficult to reduce to fine powder. Its specific gravity 

 is greater than that of any other earth, and approaches that of 

 the oxide of lead : I found it 9.402. The specific gravity of 

 the mineral thorite is therefore considerably less than might 

 be expected from that of the pure earth. 



Before the blowpipe, it remains unchanged ; with borax it 

 melts with very great difficulty, and the clear glass does not 

 lose its transparency by flaming'^ ; but it may be saturated so 

 much as to become milky on cooling. In phosphoric salt, it 

 dissolves with great difficulty, and with carbonate of soda it does 

 not fuse. 



The saturating power of thorina I have endeavoured to 

 determine by the analysis of its combination with sulphuric 

 acid. The sulphate, precipitated by boiling, was afterwards 

 dissolved in cold water, and the solution precipitated by pure 

 caustic potash in slight excess. The earth, fully washed and 

 * An intenuitting application of the flame* 



