and you will readily perceive that the human
muscles, or even the muscles of a horse, would be more expensive
still. Here, however, we can employ the force of burning coal to turn
our machine, and it is this employment of our cheapest fuel, rendered
possible by Faraday's discovery, which opens out to us the prospect of
being able to apply the electric light to public use.

In 1866 a great step in the intensification of induced currents, and
the consequent augmentation of the magneto-electric light, was taken
by Mr. Henry Wilde. It fell to my lot to report upon them to the
Royal Society, but before doing so I took the trouble of going to
Manchester to witness Mr. Wilde's experiments. He operated in this
way: starting from a small machine like that worked in your presence a
moment ago, he employed its current to excite an electro-magnet of a
peculiar shape, between whose poles rotated a Siemens armature;
[Footnote: Page and Moigno had previously shown that the
magneto-electric current could produce powerful electro-magnets.] from
this armature currents were obtained vastly stronger than those
generated by the small magneto-electric machine. These currents might
have been immediately employed to produce the electric light; but
instead of this they were conducted round a second electro-magnet of
vast size, between whose poles rotated a Siemens armature of
corresponding dimensions. Three armatures therefore were involved in
this series of operations: first, the armature of the small
magneto-electric machine; secondly, the armature of the first
electro-magnet, which was of considerable size; and, thirdly, the
armature of the second electro-magnet, which was of vast dimensions.
With the currents drawn from this third armature, Mr. Wilde obtained
effects, both as regards heat and light, enormously transcending those
previously known. [Footnote: Mr. Wilde's paper is published in the
'Philosophical Transactions 'for 1867, p. 89. My opinion regarding
Wilde's machine was briefly expressed in a report to the Elder
Brethren of the Trinity House on May 17, 1866: 'It gives me pleasure
to state that the machine is exceedingly effective, and that it far
transcends in power all other apparatus of the kind.']

But the discovery which, above all others, brought the practical
question to the front is now to be considered. On the 4th of
February, 1867, a paper was received by the Royal Society from Dr.
William Siemens bearing the tit