94 SALINES. [IV. 



Warrington found that in decolorizing beer by charcoal, the 

 hop-bitter was also removed ; and that decoctions of Peruvian 

 bark and solutions of sulphate of quinin, and acetates of 

 morphin and strychnin, were freed from their bitter. 12 gr. 

 bone-black were required for 2 gr. sulphate of quinin dissolved 

 in 2 oz. water. An infusion of nux vomica was not debitterized 

 by animal charcoal. 



Eisner found that salicin was wholly removed from solution 

 by filtration through common bone-black, as well as that freed 

 from lime by muriatic acid ; and that the coal digested with 

 alcohol again yielded up its salicin. Strychnin, brucin, qui- 

 nin, and cinchonin are removed from their hot aqueous solu- 

 tions by bone-black or well-ignited wood-charcoal. A large 

 excess of bone-black and charcoal sweetened a concentrated 

 decoction of nux vomica. Solutions of aloes, lupulin, quassia 

 are debitterized, and a solution of nitropicric (carbazotic) acid 

 by bone-black freed from lime. 



Weppen further observed that a charcoal which has been 

 used for precipitating one metal, may still be used for pre- 

 cipitating another. Thus, 200 gr. coal, which had been used 

 for precipitating a solution of corrosive sublimate, were shaken 

 with a solution with 5 gr. blue-vitriol in 2| oz. water, when in 

 a short time only a trace of copper was left in the liquid, and 

 disappeared altogether upon adding ammonia. After washing 

 and drying the coal, it was shaken with a solution of 3 gr. 

 copperas, from which it soon removed all traces of iron. 

 (Journ, f. Pr. Chem. xxxix. 318.) 



2. Sulphur and Sulphuric Acid. — This most important of 

 all acids to the chemist, as the source of all others, is made 

 by burning sulphur to sulphurous acid, and oxidizing this to 

 sulphuric by nitric acid, or the oxides of nitrogen. Exclusive 

 regulations of the Neapolitan government have developed the 

 important fact that pyrites (sulphuret of iron) will answer the 

 same end as sulphur on a manufacturing scale, and we know 

 that pyrites is a very abundant mineral. 



Sulphuric Acid. — Peligot observed, years ago, that sul 

 phurous acid gas, passed through moderately strong nitric 



