90 Royal Society. 



disturbances and divisions of the electric current produced by the 

 battery, arising from secondary combinations j the results of which 

 observations form the subject of the present paper. He found that 

 the resistance to the passage of the current was diminished by dis- 

 solving the sulphate of copper which was in contact with the copper 

 in the standard sulphuric acid, instead of water. The increased 

 effect of the current, as measured by the voltameter, was farther 

 augmented by the heat evolved during the mixture ; and wishing 

 to study the influence of temperature in modifying these effects, 

 the author placed the cells of the battery in a tub, filled with hot 

 water. On charging the cells with a solution of muriate of am- 

 monia in the interior, and aqueous solution of sulphate of copper in 

 the exterior compartment, he observed that a portion of the current 

 is discharged by the water in which the apparatus is immersed ; 

 its passage being indicated by the disengagement of gas betwixt 

 the adjacent cells; in which case, one of the zinc rods is thrown 

 out of action, and the copper of that cell acts merely as an electrode 

 to the antecedent zinc. A saturated solution of common salt was 

 next placed in contact with the zinc, while the exterior compart- 

 ments of the cells were filled with a saturated aqueous solution of 

 sulphate of copper } but the effects were much diminished. It thus 

 appeared that the substitution of solutions of the muriates for dilute 

 sulphuric acid was in every way disadvantageous ; and it was more- 

 over found that, when the circuit was broken, the copper became 

 seriously injured by their action, and by the formation of a sub- 

 muriate of that metal. 



Finding that the membranous tubes were unable to resist the 

 action of the acid under the influence of high temperatures, the au- 

 thor substituted for them tubes of porous earthenware, of the same 

 texture as that of which wine-coolers are commonly made, closed 

 at their lower ends, and of the same height as the copper cells. 

 The bottoms of the latter were fitted with sockets, for the reception 

 of the tubes, and for confining them in their proper places ; the . 

 perforated copper plates, or colanders, which held the solid 

 sulphate of copper, passing over their upper ends. The tubes can 

 be easily removed, and instantly replaced ; and the facility of 

 emptying and refilling them renders the addition of siphon-tubes 

 unnecessary, except in very particular circumstances. A cir- 

 cular steam- vessel of tin plate was then provided, around which 

 the cells could be placed upon blocks of wood, and closed in with 

 a cover, containing a socket, which could, at pleasure, be connected 

 with the steam pipe of a boiler. Two other sockets were also con- 

 veniently placed, provided with cork stoppers, through which the 

 electrodes of the battery could pass, when the proper connexions 

 were made. By using this apparatus the author determined that the 

 increase of effect consequent on an augmentation of temperature is 

 but in a slight degree dependent on an increase of conducting power 

 in the electrolyte, but arises principally from its increased energy of 

 affinity, producing a greater electromotive force. 



In heating the battery by the steamer, it frequently happened that, 



