magnet or at a distance from
it. Faraday finds distance to be perfectly immaterial so long as the
number of lines intersected is the same. For example, when the loop
connecting the equator and the pole of his barmagnet performs one
complete revolution round the magnet, it is manifest that all the lines
of force issuing from the magnet are once intersected. Now it matters
not whether the loop be ten feet or ten inches in length, it matters
not how it may be twisted and contorted, it matters not how near to the
magnet or how distant from it the loop may be, one revolution always
produces the same amount of current electricity, because in all
these cases all the lines of force issuing from the magnet are once
intersected and no more.

From the external portion of the circuit he passes in idea to the
internal, and follows the lines of force into the body of the magnet
itself. His conclusion is that there exist lines of force within the
magnet of the same nature as those without. What is more, they are
exactly equal in amount to those without. They have a relation in
direction to those without; and in fact are continuations of them....
'Every line of force, therefore, at whatever distance it may be taken
from the magnet, must be considered as a closed circuit, passing in some
part of its course through the magnet, and having an equal amount of
force in every part of its course.'

All the results here described were obtained with moving metals. 'But,'
he continues with profound sagacity, 'mere motion would not generate a
relation, which had not a foundation in the existence of some previous
state; and therefore the quiescent metals must be in some relation to
the active centre of force,' that is to the magnet. He here touches the
core of the whole question, and when we can state the condition into
which the conducting wire is thrown before it is moved, we shall then
be in a position to understand the physical constitution of the electric
current generated by its motion.

In this inquiry Faraday worked with steel magnets, the force of which
varies with the distance from the magnet. He then sought a uniform field
of magnetic force, and found it in space as affected by the magnetism
of the earth. His next memoir, sent to the Royal Society, December 31,
1851, is 'on the employment of the Induced Magnetoelectro Current as a
test and measure of magnetic forces.' He forms rectangles and rings, and
by ingenious and simple devices