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cal service while we are waiting for the actual truth to 
become known. 
The state of excitement into which iron is thrown by the 
influence of a magnet is sometimes called " magnetization 
by influence." More commonly, however, the magnetism is 
said to be " induced " in the iron, and hence this mode of 
magnetizing is called " magnetic induction." Now there 
is nothing theoretically perfect in Nature: there is no iron 
so soft as not to possess a certain amount of coercive force, 
and no steel so hard as not to be capable, in some degree, 
of magnetic induction. The quality of steel is in some 
measure possessed by iron, and the quality of iron is shared 
in some degree bv steel. It is in virtue of this latter fact 
that the unmagnetized darning-needle was attracted in 
your first experiment; and from this you may at once de- 
duce the consequence that, after the steel has been mag- 
netized, the repulsive action of a magnet must be always 
less than its attractive action. For the repulsion is opposed 
by the inductive action of the magnet on the steel, while 
the attraction is assisted by the same inductive action. 
Make this clear to your minds, and verify it by your exper- 
iments. In some cases you can actually make the attrac- 
tion due to the temporary magnetism overbalance the 
repulsion due to the permanent magnetism, and thus cause 
two poles of the same kind apparently to attract each other. 
When, however, good hard magnets act on each other from 
a sufficient distance, the inductive action practically van- 
ishes, and the repulsion of like poles is sensibly equal to 
the attraction of unlike ones. 
I dwell thus long on elementary principles, because they 
are of the first importance, and it is the temptation of this 
age of unhealthy cramming to neglect them. Now follow 
me a little farther. In examining the distribution of 
magnetism in your strip of steel you raised the needle 
slowly from bottom to top, and found what we called a 
neutral point at the center. Now does the magnet really 
exert no influence on the pole presented to its center? Let 
us see. 
Let s if, fig. 11, be our magnet, and let n represent a 
particle of north magnetism placed exactly opposite the 
middle of the magnet. Of course this is an imaginary case, 
thrown "into a state of temporary excitement, in virtue of which they 
are repelled; but any attempt to explain such a repulsion by the de- 
composition of a fluid will demonstrate its own futility. 
