400 RHODIN, ON STOR AGE BATTERIES. 



My reasoning was this. The absence of capacity depends upon 

 the cit'curastances that the current density in question is so great 

 that the layer of electrolyte which touches the metallic conductor 

 would loose its ionised molecules so quickly that the dijfusion 

 of further H 2 S0 4 molecules to this surface. ivould not be able to 

 supply enough ions for carrying the current. This would occur 

 sooner in the 6 mm. plates than in the 10 mm. plates from 

 following reason. The active sur face of a Laurent-Cely positive 

 plate is the surface where the grid or metallic lead frame work 

 touches the pieces of peroxyde of lead, as there might cdways be 

 a spaee between these pieces of peroxyde of lead and the sur- 

 face of the frame toork filled with electrolyte lohich 7night be 

 totally robbed of its ions. This surface is for a 10 mm. plate 

 equal to 10/6th of that for a 6 mm. plate approximately. Hence 

 the current density 1 for a 6 mm. plate equals the current 0.6 

 for a 10 mm. plate and in conclusion if a concentration of ions 

 equal to the unit stops the current Output of.a 6 mm. plate, 

 this density might fall to the value 0.6 before fatally impeding 

 the current Output of a 10 mm. plate. (The densities 9 end 5°B 

 fulfil these requirements approximately). This may be put down 

 as a law as follows: — 



m= K (1) 



T = current to be kept up; 



C= specific conductivity of electrolyte for which T=Q] 



S = active surface in the above sense. 



K = algebraical constant. 



I have thus shown that the concentration of the ions of the 

 electrolyte is a most important item which determines the cessa- 

 tion of current Output at a given rate — I shall now proceed to 

 treat the case, when the capacity has a finite value, and shew 

 how conditions, similar to those already mentioned, may develop 

 after a finite periocl of work. I shall again only treat the case 

 of the positive or peroxyde of lead plate. The positive Laurent- 

 Cely plate consists of slabs of peroxyde of lead kept together by 



