440 sliudijtes uj Books. [Dec. 



Carbonic acid ]G*70 



Peroxide of copper 60-J5 



Peroxide of iron lf>-50 



Silica 2*10 



Loss 0-95 



100-00 



The silica is accidental. The carbonic acid is united to the 

 copper, constituting common carbonate of copper without water, 

 which is composed of one atom carbonic acid and one atom per- 

 oxide of copper. The red oxide of iron is only mechanically mixed, 



A. The Bakerian Lecture : on some New Electro-Chemical Phe- 

 nomena. By William Thomas Rrande, Esq. F.R.S. Prof. Chem. 

 R- 1. — Mr. Cuthbertson observed that when the flame of a candle 

 is introduced between a negative and positive bail, the negative ball 

 becomes hotter than the positive. Mr. Erman has shown that 

 certain substances are unipolar with regard to the electricity of the 

 voltaic pile. The insulated flames of wax, oil, spirit of wine, and 

 hydrogen gas, only conduct positive electricity ; while the flame of 

 phosphorus conducts only negative electricity. It occurred to Mr. 

 Brande that these facts admitted of another explanation. It is 

 known that some chemical bodies are naturally positive, others 

 naturally negative. The positive of course would be attracted by 

 the negative ball, and the negative by the positive. To determine 

 the validity of this conjecture, he made a set of experiments on 

 various bodies, the results of which are related in the present 

 lecture. 



The apparatus employed consisted of two insulated brass balls, 

 the distance of which from each other could be varied at pleasure. 

 One of them was attached to the positive, the other to the negative, 

 prime conductor of an electrical machine ; and care was taken that 

 this machine should be in weak action. The following were the 

 results obtained : When olefiant gas was burnt between the balls, 

 the flame was attracted towards the negative side. The flame of 

 sulphureted hydrogen was slightly attracted to the negative side ; 

 the sulphurous acid vapour formed was attracted towards the positive 

 ball. A small flame of phosphureteil hydrogen was rather attracted 

 to the positive ball ; a large flame of this substance was equally 

 attracted by both balls. The flame of arsenicated hydrogen was 

 attracted by the negative ball ; the fumes of white arsenic were 

 slightly drawn towards the positive ball. The flame of hydrogen 

 was weakly attracted towards the negative ball, but not very 

 decjdedly so. A huge flame of carbonic oxide was attracted by the 

 positive ball. When sulphur is burnt, the vapour is attracted by 

 the positive ball. The direction of the flame could not be d< 

 mined. The frame of snlphuret of carbon was attracted to the 

 ;itive ball. The il.unc o'f phosphoRus and iis vapour • 



