142 MR. FARADAY’S EXPERIMENTAL RESEARCHES IN ELECTRICITY. 
to itself in the iron, rendering it a magnet. This is known by experiment to 
occupy time ; for a magnet so formed, even of soft iron, does not rise to its 
fullest intensity in an instant, and it may be because the currents within the 
iron are successive in their formation or arrangement. But as the magnet can 
induce, as well as the battery current, the combined action of the two continues 
to evolve induced electricity, until their joint effect is at a maximum, and thus 
the existence of the deflecting force is prolonged sufficiently to overcome the 
inertia of the galvanometer needle. 
70. In all those cases where the helices or wires are advanced towards or 
taken from the magnet (50. 55.), the direct or inverted current of induced 
electricity continues for the time occupied in the advance or recession; for the 
electro-tonic state is rising to a higher or falling to a lower degree during that 
time, and the change is accompanied by its corresponding evolution of electri- 
city ; but these form no objections to the opinion that the electro-tonic state 
is instantly assumed. 
71. This peculiar state appears to be a state of tension, and may be consi- 
dered as equivalent to a current of electricity, at least equal to that produced 
either when the condition is induced or left at liberty. The current evolved, 
however, first or last, is not to be considered a measure of the degree of tension 
to which the electro-tonic state has risen ; for as the metal retains its conduct- 
ing powers unimpaired (65.), and as the electricity evolved is but for a moment, 
(the peculiar state being instantly assumed and lost (68.),) the electricity which 
may be led away by long wire conductors, offering obstruction in their sub- 
stance proportionate to their small lateral and extensive linear dimensions, 
can be but a very small portion of that really evolved within the mass at the 
moment it assumes this condition. Insulated helices and portions of metal 
instantly assumed the state ; and no traces of electricity could be discovered 
in them, however quickly the contact with the electrometer was made, after 
they were put under induction, either by the current from the battery or the 
magnet. A single drop of water or a small piece of moistened paper (23. 56.) 
was obstacle sufficient to stop the current through the conductors, the elec- 
tricity evolved returning to a state of equilibrium through the metal itself, 
and consequently in an unobserved manner. 
72 . 'fhe tension of this state may therefore be comparatively very great. 
