Professor Berzelius on Thorina, 103 



a solution but by evaporating to dryness, and destroying the 

 tartaric acid by a red heat. 



Tartrate of thorina and potash is formed when bitartrate of 

 potash is digested with hydrate of thorina and water. It is a 

 difBcultly soluble crystalline salt, which is not precipitated 

 by alkalies, and is only rendered opalescent by prussiate of 

 potash. 



Citrate of thorina. — When citric acid is digested upon 

 hydrate of thorina, a white flocky insoluble neutral salt is ob- 

 tained, while super-salt remains in solution, which may be 

 evaporated to a transparent syrupy mass, but does not crystal- 

 lize. Its taste has more sourness than astringency. Both 

 the neutral and the super-salt dissolve with ease in caustic 

 ammonia, without any sign of precipitation ; and if the solution 

 be concentrated, there is obtained from both a transparent 

 gummy-like mass, which is soluble in water. To obtain the 

 thorina, therefore, the citric acid, like the tartaric, must be 

 destroyed. 



Acetate of thorina. — If hydrate of thorina, still wet, be 

 digested with dilute acetic acid, a thick pasty opaque mass is 

 formed ; and if carbonate of thorina be digested with concen- 

 trated acetic acid, it is decomposed with eflfervescence, a white 

 powder remaining at the bottom, and a small quantity being 

 taken into solution. Either of these being evaporated nearly 

 to dryness by a gentle heat, the acetate of thorina becomes in- 

 soluble in water ; and it may in this way be freed from other 

 earths, which dissolve in the form of acetates, while only a 

 slight trace of thorina is taken up. The acetate is heavy, ena- 

 mel-white, and goes like milk through the filter, unless the 

 washing-water contain a little muriate of ammonia. From the 

 neutral nitrate of thorina, acetate of potash causes no preci- 

 pitate, not even by boiling, which seems to indicate the forma- 

 tion of a soluble double salt. 



Succinate of </iori/ia.— Succinate of ammonia throws down 

 from the neutral salts of thorina a white flocky precipitate. 

 The hydrate of thorina, digested with a solution of succinic 

 acid, changes into a thick enamel-white neutral salt, like the 

 acetate. Excess of succinic acid dissolves only a trace of the 

 neutral salt. 



Formate of thorina, — Formic acid dissolves the hydrate of 



