186 M. E. Edlund on the Xature of Electricity. 



cedure Dr. Suudell lias made some experiments^ which have 

 given no certain appreciable results ; and this likewise cor- 

 roborates the theoretic deduction explained above. 



The true law of induction between two elements is therefore 

 expressed by the above-given formula (20). In virtue of the 

 principles on vrhich our present theoretic investigations are 

 founded, it is evident that the formula in question applies also 

 to the case in wliich induction takes place witli a current of 

 constant intensity, resulting from the distance between the in- 

 ducing element ds and the induced element ds diminishing 

 from infinity to ?*. 



5. Distribution of the free cEther at rest upon the conducting 

 ivire between the two jwles of a battery. — When a conducting 

 wire with considerable resistance connects the poles of a galvanic 

 battery, there is produced, as we know, free electricity at the 

 surface of the rae. The positive electricity exhibits its maximum 

 tension in the vicinity of the positive pole. With increasing- 

 distance from this the positive electricity diminishes ; and if the 

 resistance of the wire is the same in every part of its length, 

 there exists in tlie centre an indifferent point, beyond which the 

 second half of the wire shows itself negatively electric, with a 

 tension which increases towards the negative pole. "When the 

 resistance of the wire is greater towards one extremity than 

 towards the other, the indifferent point is nearer the same ex- 

 tremity as the greatest resistance. The difference between the 

 electrical tensions at two points in the wire, divided by their 

 mean resistance to conduction^ is eveiywhere constant. This 

 position of equilibrium of" free electricity appears difficult to 

 explain ; for it seems that the negative and positive electricities 

 ought to clear the indifferent point and combine. Xor in this 

 respect has any explanation been hitherto given satisfactory and 

 free from all arbitrary hypothesis. The theory now presented 

 offers, as of itself, that explanation : — AVhen a galvanic cm-rent 

 commences, the molecules of the surrounding mass of gather 

 abandon the positions of equilibrium which they have hitherto 

 occupied, and pass into new positions ; hence there results an 

 induced current in a neighbouring closed conductor. The 

 molecules which are in a nonconducting body near are also 

 driven from their positions of equilibrium, and take new ones, 

 although the absence of conductivity prevents the rise of an 

 induction-current properly so called. The molecules remain in 

 their new positions of equihbrium as long as the active cause 

 (the galvanic current) continues with constant force. The lav/ 

 of the action of an element of the inducing current upon an 

 element of the induced current is expressed by the formulae given 

 above. But it is evident that it must be altogether the same 



