256 



On the Che.mk.al Examination of 



Tersulphuret c, , . Sulphur, 



of Arsenic. *^ hxa ' percent. 



500 grains gave 5-16 1-932 -386 



Estimation of Phosphate of Lime. — The insoluble salts hav- 

 ing been dissolved in acid and the silica separated, the phos- 

 phate of lime was precipitated by ammonia. 





400 grains gave 

 500 -- 





oOO 



Phosphate 

 of Lime. 



42-84 

 52-50 

 52-30 



Mean, 



Phosphate of 1 

 per cent. 



10-71 



10-50 

 10-46 

 10-556 



Estimation of Alumina. — To ascertain if the phosphate of 

 lime contained alumina, it was dissolved in acid, and then 

 boiled in an excess of strong caustic soda, which would re- 

 dissolve any alumina. It was found that it contained a 

 small quantity, which was probably accidentally introduced 

 by the caustic soda, or other reagents. 



Alumina. 



400 grains gave 

 500 



•748 



•500 



Mean, 



Alumina, 

 per cent. 



•185 

 •100 

 •1425 



Determination of Lime. — To the liquid from which the 

 phosphate of lime had been separated oxalate of ammonia 

 was added, when oxalate of lime fell. This precipitate being 

 washed and heated to redness was converted into carbonate. 



Lime 



ai6%V/q*3¥&od $Bw mi «r- flft^ 

 500 grains gave 38-85 21-755 4-351 ; , 



Estimation of Magnesia, — Having removed the lime by 

 filtration, the magnesia was precipitated by means of phos- 

 phate of soda and ammonia, as the ammonia-phosphate of 

 magnesia, which when heated was converted into the diphos- 

 phate of magnesia [2(MgO)P0 5 ]. 



2(MgO)P05 Magnesia. 



Magnesia, 

 per cent. 



- ^/^i - < He. 



500 grains gave 43-70 15-60 3'Mdq 



The results of the preceding analyses are comprehended 

 in the following table : — 



Nitrogen -6585 



Hydrogen, -144 



Carbon, ...... *920 



