18 Law of the Induction of an Electric Current upon tiself. 
is produced in an opposite direction to the induced current at the 
beginning of the primary current.” 
My purpose in this paper is to present certain deductions from 
these laws in reference to the induction upon itself of an initial elec- 
tric current moving in a straight conductor. In arriving at these 
laws of electricity to admit of very serious doubt. Still they 
he very simple and sufficiently elegant analytical result arrived 
Prof. Henry’s laws, with the hypotheses assumed as the 
basis of the present investigation, may be summed up in the fol- 
lowing enunciation. . 
The inductive force exerted at a given point by the development — 
of an electric current in an infinitely short element of an infix 
nitely attenuated conducting wire, is directly proportional to the — 
rapidity with which the current increases in quantity (or the rate — 
> 
Let ab, fig. 1, be an infinitely short ele- | 
ment of an electric current flowing with in- 
creasing rapidity in the direction of the arrow, 
and let ¢ be any point within the space of its 
sensible action: join bc and draw the perpen- 
dicular af. We have the analogy of thedy- + | 
namical action of galvanic currents for believing that the induc- 
tive effect of the elementary current will be the saine whether it 
move through the straight line ab or through the route afb. 
* The most serious + sige it appears to me, that can be raised in regard to these 
r g the nature of the induction of a current upon itself, is whether 
he action designated by that name is really due, as Prof. Henry believes, to inductive 
“action at a distance only, or may not be partly due to a different species of 
_ more strictly analogous to inertia in atter. P 
‘more in accordance with the icity of nature’s operations, and at pres 
s not, so far as I am aware, any special reason to doubt its correctness. 
I hope to be able to settle the question hereafter by experiment. 
