Law of the Induction of an Electric Current upon itself. 31 
19. In fig. 9, let the conductor abcd be cut longitudinally by 
two parallel planes whose intersections with the spherical surface 
. . form the zone fehklm. he area of this zone is simply pro- 
portional to the distance between the two planes, and therefore by 
what we have just seen, the same is true of the rate of develop- 
ment of current in the plate of metal included between the cut- 
ting planes, and the same relations will obviously exist with the 
: quantity of current, at any given instant of time as with the rate 
i of development. 
20. From this it would appear that if an electric jar or battery 
4 were discharged through a cylindrical conductor composed of flat 
metallic plates of equal thickness, in the manner represented in 
fig. 10, each plate, whether the wide certtral ones or the narrower 
aca near the sides, would conduct the same part of the whole 
| charge. ‘ 
. amin saennasen, 
ans nenn seen eton a. 
Pra 
oor 
"J Oa 
bias Peete ae i Su vel Bs p 
meee, ignuses®? a tl path og 
_It is manifest however, from an inspection of the figure, that ex- 
| treme = ‘ 1 : 
\ 
