* 2 
a. 
On Electro-Dynamic Induction. 151 
' be supposed to be more rapid at the first moment, than after 
_ it has lost somewhat of its intensity, or sunk more nearly to its 
normal state. These variations are indicated by the rapid rise of 
the curve, Fig. 17, from A to g, and the more gradual increase of , 
the ordinates from h to B; and by the rapid diminution of the 
ordinates between © and J, and the gradual decrease of those to- 
wards the end of the curve. 
89. These more minute considerations, relative to the form of 
the curve, will enable us to conceive, how the time of the end- 
ing of the secondary current, as we have suggested, (78,) may 
be prolonged beyond that of the natural subsidence of the dis- 
turbance of the electricity of the conductor on which this current 
depends. If the development of the primary current is produ- 
ced by equal increments in equal times, as would be the case in 
plunging the battery (59) into the acid with a uniform velocity ; 
then the part AB of the curve Fig. 17, would be a straight line, 
and the resulting secondary current, after the first instant, would 
be one of constant quantity during nearly the whole time repre- 
sented by Ac; but if the rate of the development of the primary 
current be supposed to vary in accordance with the views we 
have given in the last paragraph, then the quantity of the secon- 
dary current will begin to decline before the termination of the 
induction, or as soon as the increments of the primary begin to 
diminish ; and hence the whole time of the subsidence of the 
secondary will be prolonged, or the length of bC, Fig. 20, will 
be increased, the descent of BC be more gradual, and the inten- 
sity of the ending induction of the secondary current be dimin- 
ished: (see Jast part of paragraph 78.) 
90. Besides the considerations we have mentioned, (88,) there 
are others of a more obvious character, which would also appear 
to affect the form of particular parts of the curve. And first we 
might perhaps make a slight correction in the drawing of Figs. 
17, 18, &c., at the point A, in consideration of the fact that the 
very first contact of the end of the conductor with the surface of 
the mercury is formed by a point of the metal, and hence the 
increment of development should be a little less rapid at the first 
Moment than after the contact has become larger; or in other 
words, the curve should per a little less abruptly from 
the axis at the point A. Also Pace has stated* that he finds 
Mii. 
* Vide this Journal, Vol. xxxv, p. 166. 
