66 



ELECTROTYPE PROCESSES. 



apart in the copper solution of second cell. The mould in the 

 single cell had gained 100 grains and the zinc plate lost 108 grains. 

 The mould in the battery cell of the other arrangement had only 



deposited upon it 30 

 grains, the zinc plate 

 had lost 35 grains: 

 but the mould in the 

 second or decomposi- 

 tion cell had also de- 

 posited upon it 30 

 grains, making in all 

 60 grains deposited, for 

 35 zinc dissolved, but 

 losing nearly double 

 the time. These ar- 

 rangements, as we 

 have before observed, 

 are simply a modifica- 

 Figures 32 and 33 represent troughs adapted to f.j on O f a sm o-l e p a i r 

 operations of this kind. In the first of these figures f -r\ n? \ J 

 a battery is represented in connection. The latter ol Darnell S Dattery 

 figure represents a trough adapted for several metals connected with a de- 

 atone operation, composition cell, the 

 advantages of which are not applicable to any other battery, as in no 

 other battery does decomposition take place within the battery cells. 

 Size of the Electrodes- When a separate battery is used for the 

 purpose of depositing in a decomposition cell, there are several con- 

 ditions which are well to be observed, as they influence the amount 

 and character of the deposit. The first is the size of the electrodes 

 in relation to the zinc in the battery. The results we have obtained 

 may be expressed in general terms. When the deposit upon elec- 

 trodes of the same size as the zinc plates in a Wollaston's battery 

 equals 100, that upon electrodes one half the size of the zinc plates 

 in the battery will be equal to 57, and upon electrodes double the 

 size of the zincs of the battery 190; but this last condition is affected 

 by the intensity of the arrangement. 



Relative Power of Batteries. The following experiments, made 

 with electrodes double the size of the zinc plates of the batteries, all 

 at equal distances (1 inch apart), will show the relative power of the 

 batteries. The time in action was one hour each: only one pair of 

 plates constituted the battery. 



Grove's battery deposited . 104 grains. 



Single cell 62 



Darnell's 33 



Smee's 22 . 



WoUaston's . 18 



