312 On Ellectrotyping Operations of the U. S. Coast Survey. 
arrangement has to traverse every battery in the chain, R will 
be multiplied as as times as we multiply E. The formula 
then becomes Q== . When the value of r and R are 
aS 
nearly equal, and we have batteries of definite construction to 
work with, it becomes a matter of some importance to determine 
whether we shall use the whole galvanic apparatus, as a sing 
electrical equivalent, by connecting all the similar parts of all 
be battery cells, or whether we shall convert it into a battery of 
Fx irs, in consecutive order, by joining dissimilar ends. 
ai ividing the battery is doubling R, and to double the electrical 
equivalents is also to double R, we shall i no bas R fourfold by the 
double arrangement. Instead of Q =R7 “we haveQ= TRar 
Taking R=r we have Q=:50 in the single arrangement, and 
Q=-40 in the double—showing that we may double the ex- 
pense, and yet make the casting more slowly than rast Con- 
ditions as ae are of frequent occurrence, and a knowledge of 
them without experimenting is of very great sage 
‘For R=107, with a single equivalent of battery, = 416" 
0:0909. For two batteries in series Qasr a0 166. The 
use of two batteries in consecutive order, as thus exhibited, 
doubles the expense, but does not double the effect. A rega 
for economy prohibits us from further increasing the series. “To 
E 2k 
represent an effect double of rs we have 7) s=)= = OR4r 
eer eS 
As As dividing R by 2 is doubling the battery surface, we may now 
ke Q=-183. The gain per cent., now indicated by doubling 
de ich makes it advantageous to make this increase when 
two consecutive batteries are used. 
The difficulty of obtaining large flat plates of silver proved @ 
serious obstacle in effecting an increase of battery vas te wd 
os jrregularity of = surface requires the plate to be placed 
e from the zinc, thereby augmenting R, the 
po thing sought to ie diminished. 
Plates could be made flat by the planishing hammer ; but the 
operation being expensive, and the plates ereeeey”! ‘liable fe 
accidents in use, economy prohibited this mode of nbier 
plates. Though the plating of metallic bodies with aipeee 
been well executed, it had not yet been determined that ang 
casting of silver could be executed in a desirable manner, and a? 
a moderate expense and trouble. At first, every attempt tomake 
