am strongly inclined to hold the electric current, pure and
simple, to be a motion of the ether alone; good conductors being so
constituted that the motion may be propagated through their ether
without sensible transfer to their atoms, while in the case of bad
conductors this transfer is effected, the transferred motion appearing
as heat.[2]

I do not know whether Faraday would have subscribed to what is here
written; probably his habitual caution would have prevented him from
committing himself to anything so definite. But some such idea filled
his mind and coloured his language through all the later years of his
life. I dare not say that he has been always successful in the treatment
of these theoretic notions. In his speculations he mixes together light
and darkness in varying proportions, and carries us along with him
through strong alternations of both. It is impossible to say how a
certain amount of mathematical training would have affected his work.
We cannot say what its influence would have been upon that force of
inspiration that urged him on; whether it would have daunted him, and
prevented him from driving his adits into places where no theory pointed
to a lode. If so, then we may rejoice that this strong delver at the
mine of natural knowledge was left free to wield his mattock in his own
way. It must be admitted, that Faraday's purely speculative writings
often lack that precision which the mathematical habit of thought
confers. Still across them flash frequent gleams of prescient wisdom
which will excite admiration throughout all time; while the facts,
relations, principles, and laws which his experiments have established
are sure to form the body of grand theories yet to come.

Footnotes to Chapter 14

[1] Mr. Clerk Maxwell has recently published an exceedingly
important investigation connected with this question. Even
in the non-mathematical portions of the memoirs of Mr.
Maxwell, the admirable spirit of his philosophy is
sufficiently revealed. As regards the employment of
scientific imagery, I hardly know his equal in power of
conception and clearness of definition.

[2] One important difference, of course, exists between the
effect of motion in the magnetic field, and motion in a
resisting medium. In the former case the heat is generated
in the moving conductor, in the latter it is in part
generated in the medium.

Chapter 15