94 Professor Berzefius on Thorina, 



great degree, insoluble both in water and acids; and that 

 thorina is precipitated by the cyanide of iron and potassium, 

 by which the salts of zirconia are not troubled. 



From protoxide of cerium, by these, that, in drying and heat- 

 ing to redness it does not assume the colour of the peroxide of 

 cerium ; and that before the blowpipe with borax and phos- 

 phor salt it does not give a coloured glass, either when hot or 

 cold, provided the earth has been previously perfectly free from, 

 oxide of iron. 



From titanic acid, as well by its precipitating with sulphate 

 of potash as by the characteristic properties of titanic acid 

 before the blowpipe. 



From the common metallic oxides^ among which, from its^ 

 high specific gravity, it might be ranked, by its not being pre- 

 cipitated by sulphuretted hydrogen. 



The properties which I have formerly stated it to possess in. 

 common with the sub-phosphate of yttria are the following : — 

 i. Its salts have a pure astringent taste, ii. The crystallized 

 sulphate treated with warm water becomes opaque, and leaves 

 a white skeleton of the crystalline form. iii. Most of its salts 

 are precipitated by boiling, and attach themselves strongly to 

 the sides of the glass like a white enamel, iv. Its hydrate 

 strongly attracts carbonic acid from the air while drying. 

 V. And dissolves in carbonated, but not in caustic alkalies. 

 vi. And the solutions of both are precipitated by prussiate of 

 potash, &c. But it is easily distinguished from yttria, both by 

 the abovementioned test and by this— that the chloride of 

 thorium is not thrown down by boiling, like a solution of sub- 

 phosphate of yttria in muriatic acidx 



3d. Thorium and sulphur. When a mixture of thorium 

 and sulphur is heated, first the sulphur begins to distil over, 

 and afterwards the metal takes fire in the gaseous sulphur, and 

 burns with nearly the same lustre as in the open air. The 

 product is a yellow powder, which by pressure becomes shining, 

 but does not exhibit the metaUic streak. Heated in an open 

 glass-tube, it gives thorina and subhmed sulphur, (even after 

 the sulphuret of thorium has been heated to redness in a 

 stream of hydrogen gas,) but it does not burn with any degree 

 of lustre. Digested with dilute acids, it gives off at first a 

 small quantity of sulphuretted hydrogen, but is not sensibly 

 dissolved even when heated. Nitric acid also acts upon it very.. 



