Chemical Science. 181 



to the received notion, diluted alcohol is more readily acted upon 

 and changed by lime than that which, by concentration, has been 

 deprived of a part or the whole of its water. 



13. Melaina, or die Black Principle of Sepia. — M. Bizio, during 

 a chemical investigation of the ink of Sepia, has found reason to 

 distinguish the black substance contained in it from all other sub- 

 stances, in consequence of its properties, and has called it Melaina. 

 It may be obtained in a pure state, he says, by heating the black 

 substance of sepia in a water-bath, with a mixture of 1 part nitric 

 acid and 1 1 of water, until the liquor becomes of a yellow colour ; 

 it is then to be removed, to have much distilled water added to it, 

 and to be filtered ; is then to be boiled repeatedly in distilled 

 water, washed in an alkaline, subcarbonate, then again washed 

 with cold water, and will thus be obtained pure. 



This substance is perfectly black, insipid, inodorous, heavier 

 than water, unchanged in the air. It does not affect test papers ; 

 it is insoluble in cold water, but dissolves in hot water, forming a 

 very black solution. Alcohol and ether do not dissolve it. The 

 aqueous solution is perfectly precipitated by sulphuric, nitric, or 

 muriatic acid, but oxalic, citric, and acetic acids do not produce 

 this effect; neither does alcohol or bi-chloride of mercury render 

 the solution turbid. Cold sulphuric acid dissolves it, heat applied 

 causes decomposition, and sulphurous acid is produced. Cold 

 nitric acid acts upon it, liberating pure nitrogen ; heat applied 

 invigorates the action, evolving nitric, oxide, &c. ; muriatic acid, 

 either cold or hot, scarcely acts upon it. The caustic alkalies 

 dissolve the substance readily, especially when heat is applied, 

 and a viscid black solution is produced ; acids precipitate it again, 

 leaving a clear solution. When introduced into a flame, it burns 

 suddenly. On a hot iron it separates, as if gaseous or vaporous 

 matter was passing off, and when heated in close vessels, yields 

 unequivocal indications of the presence of nitrogen. — Giornale de 

 Fisica, viii. 105. 



14. Analysis of the Solanum Pseudo-Quina.—M. Vauquelin has 

 produced an elaborate analysis of the bark of the solanum pseudo- 

 quina, and finds it to contain a bitter principle, purely vegetable, 

 to which it owes its virtues, and amounting to 8 per cent., a resin- 

 ous matter, about 2 per cent. ; a small quantity of viscid fatty 

 matter ; a very abundant animal substance, which, in consequence 

 of being combined with sub-malates of potash and lime, presents 

 alkaline characters; starch, in minute quantity ; oxalate of lime, 

 5 or 6 per cent. ; malates of lime and of potash ; carbonate of lime, 

 5 per cent. ; oxide of manganese, in notable quantity, united to 

 malic and oxalic acids ; malate of iron, a minute portion of mag- 

 iwiWdn an atom of phosphate of lime, and ligneous matter, amount- 

 ing to two-thirds of the whole weight. 



