Prof. PoweH's 'Notes on Repulsion by Heat, S^c. SI 7 



tion) eliminated at it. But no perceptible trace of this metal 

 is deposited there, however long the voltaic pair may act upon 

 the copper solution. Now we ask, by what means is the 

 electrolyzing power of the current, which proceeds from the 

 deoxidation of the peroxide, counterbalanced ? No doubt 

 by a second current, which as to direction is opposite, and as 

 to strength equal to, the first current. But whence such a 

 second stream ? I do not know any source to which it can be 

 assigned but to the union of the sulphuric or nitric acid with 

 the protoxide of lead, though I am well aware of Mr. Faraday's 

 high authority being against such a supposition, which does 

 not allow this sort of chemical action to be a cause of current 

 electricity. Nobody knows better than I do that the re- 

 markable voltaic action of the peroxides is very far from 

 having been sufficiently cleared up by my researches ; I hope, 

 however, that the interesting subject will be taken up by abler 

 hands than mine ; and I particularly wish that the British 

 philosophers, who generally take so lively an interest in every- 

 thing relating to electrical science, would engage themselves 

 in investigating the matter still further. 



Your most humble and obedient servant, 



Bale, Feb. 18, 1838. C. F. Schcenbein. 



XLVIII. Notes on Repulsion by Heat, S^c, By the Rev, 

 Baden Powell, M,A,, F,R,S., JP.G.5., Savilian Professor 

 of Geometry, Oxford, 



To the Editors of the Philosophical Magazine and Journal, 



Gentlemen, 



N the Philosophical Transactions* for 1834?, part ii. there 

 is inserted a paper in which I described an experiment for 

 establishing without difficulty or ambiguity the existence of 

 a repulsive power exerted between heated surfaces at small 

 though sensible distances, viz. at those intervals at which the 

 colours of thin plates are formed ; the repulsive effect being 

 indicated by the instantaneous descent of the tints in the 



* See also Reports of British Association, vol. iii. (or Fourth Report) 

 p. 549; andJournal of Franklin Institute, U.S., Feb. ] 836. (and L. & E. 

 Phil. Mag., vol. vi. p. 58.] 



I regret to observe in a synopsis of the analogies of light, heat, &c. in 

 the British Annual of this year, this property of repulsion is mentioned as 

 doubtful, without any reference to my experiments ; which is the more re- 

 markable, as an account of them was given in one of the early Numbers 

 of the Records of General Science, by the same Editor. 



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