GROVE'S BATTERY. 39 



easily arranged. Care, however, must be taken, when fitting up 

 such an arrangement, that the platinum be kept closely connected 

 with the zinc by a large surface, 

 otherwise the platinum will be 

 fused at the connections. A flat 

 piece of wood, with a groove to fit 

 the zinc, is often made the means 

 of keeping the two metals together; 

 but we prefer flat binding screws 

 of brass, for if kept clean they assist 

 the connection, being good con- 

 ductors. The fusion of the plati- 

 num connections, a practical and 

 often expensive annoyance, may, 17. 



however, be completely prevented 



by coating about half an inch of the end of the platinum, either with 

 copper or silver, which is easily effected by the electro-process : the 

 coated part is then connected with the zinc by any convenient means 

 without the risk of fusing. 



Figure 17 represents a Grove's battery of eight cells complete. 

 Its parts are as follows a, >, binding screws connected with the 

 terminal poles of the battery ; c, binding screw to be used when 

 only half the cells are required ; d, band connecting the zinc plates 

 to the screw b; e, band connecting the platinum plates to the screw 

 a; g, porous cell; #, platinum plate; 2, zinc plate; &, binding screw 

 to connect the zinc to the platinum. 



This form of battery is also free from some of the objections to 

 the common battery, but it is seldom or never used in the ordinary 

 processes of electro-metallurgy. Its advantages over every other 

 known form of battery are, its great activity of action, and intensity, 

 or power, of current a circumstance not generally sought after by 

 electro-metallurgists. But if it were duly considered that a battery 

 consisting of three pairs of zinc and platinum is far more effective 

 than an ordinary battery of ten or twelve pairs (although the ele- 

 ments of its construction are more expensive), it would stand a fair 

 chance of being adopted as the more economical battery of the two. 



The porous cells have not the objection of being closed up by the 

 deposition of metals upon or within them ; but they are affected by 

 the acids, and by long working they become too porous, the nitric 

 acid passing through and causing rapid destruction of the zinc. It 

 wants the constancy of Daniell's, its quantity declining rapidly when 

 long in action one feature we have often experienced which we 

 have not seen observed by other experimenters. When working 

 with a Grove's battery of from eight to twelve pairs, the platinum 

 being six inches by seven inches, after the battery was in action for 



