Professor Berzelius on Thorina. 101 



saturated solution of sulphate of potash. It dissolves with dif- 

 ficulty in cold water, but very easily and readily in warm. 

 Left to spontaneous evaporation, the solution deposits clear 

 colourless crystals, which I once obtained in the form of rec- 

 tangular four-sided prisms united lengthwise into a cross, formed 

 of the plane terminations of the prisms. But these crystals 

 seemed to be hemitro{)ic, and had re-entering angles on the 

 projecting (ut at vande) sides of the prism. These crystals I 

 have generally obtained too small to determine their form more 

 nearly. 



The aqueous solution of this salt, boiled in a platina vessel, 

 speedily covers the metal with a layer of thorina, and deposits 

 a subsalt insoluble in water ; but this decomposition goes on 

 only to a certain degree, and that which is deposited speedily 

 loses a portion of its acid. The salt is insoluble in alcohol. It 

 contains water of crystallization, which is dissipated by a gentle 

 heat, and leaves the crystals opaque and milk-white. It is not 

 changed by exposure to the air. It consists of 

 Sulphuric acid =3 9.3 12 



= KS+ThS+H 



I have been unable to form any double salt of these consti- 

 tuents in any other ratio. Even the acid sulphate of potash, 

 melted with thorina, produces this salt ; but it is not dissolved 

 by melting in an excess of this acid salt, as is the case with 

 zirconia, tantalic acid, titanic acid, &c. 



Nitrate of thorina dissolves easily in water and alcohol. In 

 the open air the solution becomes syrupy and semi-fluid. Over 

 sulphuric acid, in a close vessel, it concretes into a crystalline 

 mass. 



Nitrate of thorina and potash is very easily dissolved in 

 water. After spontaneous evaporation to the state of syrup, it 

 shoots out all at once into a mass of strawlike crystals. It is 

 soluble in alcohol. 



Phosphate of thorina is insoluble even in excess of phos- 

 phoric acid. It falls in the form of a white flocky precipitate, 

 melting with difiSculty before the blow-pipe. 



Borate of thorina is a white flocky precipitate, insoluble in 

 excess of boracic acid. 



