208 



M. Berzelius on Thorite and Thorina. 



new Thorina, which, however, I afterwards found not to be the 

 case. This resemblance is the reason why I called the new 

 earth Thorina. 



The composition of the mineral is as follows : — 



The new earth, thorina, possesses the following properties : It 

 is colourless, infusible, after being strongly ignited it is inso- 

 luble in the acids, except the sulphuric acid ; nor does it become 

 soluble on being heated with alkaline substances. It is inso- 

 luble in caustic alkalies, but is dissolved by their carbonates. 

 The solution heated gives a precipitate of thorina, which is re- 

 dissolved on the temperature being lowered. The salts of 

 thorina have a pure astringent taste. A concentrated solution 

 of the sulphate of thorina, when boiled, coagulates into a thick 

 pulp, but is redissolved in cold water. This property forms the 

 most prominent character of the new earth. Like the salts of 

 cerium, it is precipitated by sulphate of potash, with which a 

 solution of it is saturated. The precipitate is a double salt and 

 soluble in pure water. Like yttria it is precipitated by the 

 cyanuret of iron and potassium. 



Thorina is not reduced by potassium ; but the chloride of 

 Thorium is, which may be obtained in the same way as the 

 chloride of aluminium. The reduction is accompanied with a 

 slight detonation. The result is a gray metallic powder, easily 

 soluble in muriatic acid, but very slowly in the sulphuric and 

 nitric acids. Water and alkaline bodies do not act upon the 

 metal. Thorium yields by pressure a bright metallic streak ; 

 it burns with a lustre similar to that of phosphorus in oxygen, 

 leaving the earth not melted, and colourless. 



