252 Mr. Brande on the Electro-Chemical 



process of electrism for a longer time, produce a much greater 

 effect than ensued in the first five or ten minutes. Aware of 

 the influence which very minute quantities of foreign matter, 

 and especially of the fixed alkalies, or of lime, might have in 

 producing some such appearances, and more especially recol- 

 lecting the singular results of Mr. Herschel's experiments 

 upon this subject, it became important to ascertain the absolute 

 purity of the quinia employed. I therefore examined it with 

 this view, and found it entirely soluble in strong alcohol ; when 

 dissolved in dilute muriatic acid the solution afforded no traces 

 whatever of lime to the usual tests ; but on burning a portion 

 of the above quinia in a platinum crucible, and dissolving the 

 ashes in muriatic acid, traces of lime were readily recognized 

 in the latter solution. I treated the morphia and cinchonia 

 which I had employed in the same way, but in them no traces 

 either of fixed alkali or of lime could in any way be discovered. 

 I am, therefore, induced to refer all the appearances which quinia 

 exhibits to the obstinate adhesion of a very minute quantity of 

 lime, which I have not yet been able entirely to deprive it of. 



The electro-chemical decomposition of the salts of the 

 vegeto-alkalies is very characteristic, in consequence of the dif- 

 ficult solubility of their bases. If, for instance, a solution of 

 sulphate of morphia be placed in the voltaic circuit, so as to 

 be decomposed between two plates of platinum, the negative 

 plate, if the solution be strong, becomes presently covered with 

 a white crust of morphia, which gradually falls off in films ; if 

 the solution be more dilute, the morphia falls in the form of a 

 white cloud from the negative conductor. 



The appearances are nearly similar with the solutions of sul- 

 phate of cinchonia and of sulphate of quinia. 



Supposing that some more decided results than those above 

 mentioned might be obtained by electrising mercury negatively 

 in contact of the soluble salts of morphia, cinchonia, and 

 quinia, the experiment was made with the respective sul- 

 phates of those alkalies, but no further appearances of metal- 

 lization ensued provided the salts were pure whereas any 

 alkaline impurity, though in very minute quantity, gave the 

 same equivocal appearances as had been previously obtained 

 with quinia containing a little lime. 



