CARBON. 93 



manufacture of sulphate of morphin, a considerable amount 

 of the alkaloid. It therefore follows, that the use of bone- 

 black as a decolorizing agent, is attended with loss, unless 

 treated finally for the separation of matters which, by pre- 

 cipitation, have become incorporated with it. 



Filtration through Bone-hlack and Charcoal. — The experi- 

 ments on the extraction of substances from solution by bone- 

 black and charcoal are interesting ; those by Weppen, in An. 

 der Chem. u. Pharm. Iv. 241 ; by Chevalier, in Journ. f. Pr. 

 Chem. XXXV. 356 ; by Warrington, in Phil. Mag. xxvii. 269 ; 

 by Eisner, in Berl. Gewerbe u. Industrie-Blatt, xx. 295. 



Weppen found that 30 gr. of bone-black, boiled with mu- 

 riatic acid, thoroughly washed, dried, and gently ignited, 

 extracted the following substances from their solutions : sul- 

 phates of copper, zinc, chrome and peroxide of iron, acetates 

 of lead and peroxide of iron, nitrates of nickel, cobalt, silv^er, 

 and of both oxides of mercury, tin salt, and tartar emetic. 

 One grain of the salt was dissolved in J oz. water. A trace 

 of the metal remains in solution, which no excess of the black 

 can remove, while a basic salt is precipitated on it; but those 

 oxides whose salts are soluble in ammonia are wholly pre- 

 cipitated. Oxide of lead, dissolved in potassa, is precipitated. 

 Arsenious acid in aqueous solution is but slightly thrown 

 down : iodine is removed from its solution in water. The 

 sulphosalts of antimony and arsenic, dissolved in sulphide of 

 ammonium, are separated as metallic sulphides by the black. 

 It appears to exert no influence on alkaline and earthy salts. 



Solutions of bitter extracts, as of wormwood, gentian, 

 quassia, cascarilla, buck-bean, and colocynth, are rendered 

 bitterless when the charcoal is in the proportion of 2:3; Co- 

 lumbo extract, by an equal weight of coal ; aloes, by 13 times 

 its weight ; extract of galls and solution of pure tannin, by 

 10 times their weight. Infusion of Peruvian bark is also 

 sweetened. Jalap and guaiacum are Avholly precipitated from 

 their solutions. 



Chevallier found that oxide of lead is easily completely pre- 

 cipitated from its acetate and nitrate, but not from its muriate. 



