INJURIOUS ARRANGEMENTS OF THE VOLTAIC BATTERY. 469 



whole of the batteiy evolved 0*9 of a cubic inch of oxygen and hydrogen in half a 

 minute ; the forty plates evolved 4*6 cubic inches in the same time ; the whole then 

 evolved 1 cubic inch in the half minute; the ten weakly charged evolved 0*4 of a 

 cubic inch in the time given: and finally the whole evolved 1*15 cubic inch in the 

 standard time. The order of the observations was that given : the results sufficiently 

 show the extremely injurious effect produced by the mixture of strong and weak 

 charges in the same battery*. 



1045. In the same manner associations of strong and weak pairs of plates should 

 be carefully avoided. A pair of copper and platina plates arranged in accordance 

 with a pair of zinc and platina plates in dilute sulphuric acid, were found to stop the 

 action of the latter, or even of two pairs of the latter, as effectually almost as an in- 

 terposed plate of platina (1011.), or as if the copper itself had been platina. It, in 

 fact, became an interposed decomposing plate, and therefore a retarding instead of 

 an assisting pair. 



1046. The reversal, by accident or otherwise, of the plates in a battery has an ex- 

 ceedingly injurious effect. It is not merely the counter action of the current which the 

 reversed plates can produce, but their effect also in retarding even as indifferent plates, 

 and requiring decomposition to be effected upon their surface, in accordance with the 

 course of the current, before the latter can pass. They oppose the current, therefore, 

 in the first place, as platina interposed plates would do (1011 — 1018.) ; and to this 

 they add a force of opposition as counter-voltaic plates. I find that, in a series of 

 four pair of zinc and platina plates in dilute sulphuric acid, if one pair be reversed, it 

 very nearly neutralizes the power of the whole. 



1047- There are many other causes of reaction, retardation, and irregularity in the 

 voltaic battery. Amongst them is the not unusual one of precipitation of copper 

 upon the zinc in the cells, the injurious effect of which has before been adverted to 

 (1006.). But their interest is not perhaps sufficient to justify any increase of the 

 length of this paper, which is rather intended to be an investigation of the theory of 

 the voltaic pile than a particular account of its practical application. 



Note. — Many of the views and experiments in this Series of my Experimental Re- 

 searches will be seen at once to be corrections and extensions of the theory of electro- 

 chemical decomposition, given in the Fifth and Seventh Series of these Researches, 

 The expressions I would now alter are those which relate to the independence of the 

 evolved elements of the poles or electrodes, and the reference of their evolution to 

 powers entirely internal (524. 537. 661.). The present paper fully shows my present 

 views; and I would refer to paragraphs 891. 904. 910. 917- 918. 947. 963. 1007. 

 1031. &c., as stating what they are. I hope this note will be considered as sufficient 



* The gradual increase in the action of the whole fifty pairs of plates was due to the elevation of tempera- 

 ture in the weakly charged trough hy the passage of the current, in consequence of which the exciting energies 

 of the fluid within were increased. 



MDCCCXXXIV. 3 P 



