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bility. Reasoning on the magnet as a source of electricity 
in a paper “On the Physical Character of the Lines of 
Magnetic Force” (Philosophical Magazine, s. 4, vol. III., 
p. 415), he says, “Its analogy with the helix is wonderful, 
nevertheless there is as yet a striking experimental distinc- 
tion between them ; for whereas an unchangeable magnet 
can never raise up a piece of soft iron to a state more than 
equal to its own, as measured by the moving wire, a helix 
carrying a current can develop in an iron core magnetic 
lines of force of a hundred or more times as much power as 
that possessed by itself when measured by the same means. 
In every point of view, therefore, the magnet deserves the 
utmost exertions of the philosopher for the development of 
its nature, both as a magnet and also as a source of elec- 
tricity, that we may become acquainted with the great law 
under which the apparent anomaly may disappear, and by 
which all these various phenomena presented to us shall 
become one.” Now, it was the precise and absolute manner 
in which Faraday stated the definiteness of the relation 
between the magnetism of a permanent magnet and that of 
a piece of iron magnetised by its influence, that led the 
author to enunciate in terms equally absolute and precise 
the antithesis of Faraday’s proposition. How far Faraday’s 
hopes and preconceptions of the electro-magnet as a source 
of electricity have been realized, the results described in this 
and the author’s former papers will show. Already has it 
superseded the use of the voltaic battery in every electro- 
depositing establishment of note in this country, and it is 
making rapid progress abroad. 
That the transformation of mechanical energy into other 
modes of force on so large a scale, and by means so simple, 
will find new and much more important applications than 
that above mentioned is one of the author’s most firm con- 
victions. 
In a note to his paper the author reviews the attempt by 
