the two states.  Now when a current acts by induction upon conducting matter lateral to it, it probably acts upon the electricity in that conducting matter whether it be in the form of a current or quiescent, in the one case increasing or diminishing the current according to its direction, in the other producing a current, and the amount of the inductive action is probably the same in both cases.  Hence, to say that the action of induction depended upon the mutual relation of two or more currents, would, according to the restricted sense in which the term current is understood at present (283. 517. 667.), be an error.

1111.  Several of the effects, as, for instances, those with helices(1066.), with according or counter currents (1097. 1098.), and those on the production of lateral currents (1090.), appeared to indicate that a current could produce an effect of induction in a neighbouring wire more readily than in its own carrying wire, in which case it might be expected that some variation of result would be produced if a bundle of wires were used as a conductor instead of a single wire.  In consequence the following experiments were made.  A copper wire one twenty-third of an inch in diameter was cut into lengths of five feet each, and six of these being laid side by side in one bundle, had their opposite extremities soldered to two terminal pieces of copper.  This arrangement could be used as a discharging wire, but the general current could be divided into six parallel streams, which might be brought close together, or, by the separation of the wires, be taken more or less out of each other’s influence.  A somewhat brighter spark was, I think, obtained on breaking contact when the six wires were close together than when held asunder.

1112.  Another bundle, containing twenty of these wires, was eighteen feet long:  the terminal pieces were one-fifth of an inch in diameter, and each six inches long.  This was compared with nineteen feet in length of copper wire one-fifth of an inch in diameter.  The bundle gave a smaller spark on breaking contact than the latter, even when its strands were held together by string:  when they were separated, it gave a still smaller spark.  Upon the whole, however, the diminution of effect was not such as I expected:  and I doubt whether the results can be considered as any proof of the truth of the supposition which gave rise to them.

1113.  The inductive force by which two elements of one current (1109. 1110.) act upon each other, appears to diminish as the line joining them becomes oblique to the direction of the current and to vanish entirely when it is parallel.  I am led by some results to suspect that it then even passes into the repulsive force noticed by Ampere[A]; which is the cause of the elevations in mercury described by Sir Humphry Davy[B], and which again is probably directly connected with the quality of intensity.

  [A] Recueil d’Observations Electro-Dynamiques, p. 285.