406 Dr. Thomas Thomson and Dr. Steels [June 



being again digested in water. Into this muddy liquid a 

 quantity of benzoic acid was thrown, and well stirred. 

 After standing 24 hours the whole iron was found to be 

 precipitated, while the glucina remained in solution .* The 

 benzoate of iron was collected on a filter, washed, dried, 

 and ignited. The peroxide of iron obtained weighed 3*75 

 grs. = 3*375 protoxide. On trial it appeared perfectly 

 pure. 



E. The residual solution was now mixed with ammonia, 

 which threw down a white floculent precipitate. It was 

 collected on a filter, well washed and dried. After ignition 

 it had a dirty brownish white colour, and weighed 3*182 grs. 



It dissolved in acids, forming very sweet tasted salts. 

 The sulphuric acid solution crystallized, though imperfectly. 

 The solution gave the following characters with re-agents : 



Prussiate of potash : No precipitate. 



Caustic ammonia : A white precipitate, not soluble in 

 an excess of the ammonia. 



Carbonate of ammonia : White precipitate, soluble in 

 an excess of the alkali. 



Caustic of potash : A white precipitate, soluble in an 

 excess. 



Oxalic acid : No precipitate. 



Oxalate of ammonia : No precipitate. 



Benzoate of ammonia: No precipitate. 



Tincture of nutgalls : A white precipitate. 



Gallic acid : No precipitate. 



The white matter obtained was therefore glucina. 



The preceding analysis gave the constituents of gadolinite 

 as follows : — 



Silica 6*220 - 24*880 



Yttria 11*087 - 44*348 



Protoxide of cerium . . 1*430 - 5*720 



Glucina 3*182 - 12*728 



Protoxide of iron . . . 3*375 - 13*500 



Platinum 0*450 - 1*800 



Moisture ..... 0*247 - 1*088 



25*991 - 104*064 



* It had been ascertained by experiment that benzoate of ammonia throws down 

 glucina, which benzoic acid does not ; and that, with care, the peroxide of iron 

 may be completely thrown down by benzoic acid. 



