e rule in question--when applied to the task of estimating
the worth of inventions claiming to produce revolutionary effects in
any industry--is necessarily, in the majority of cases, more or less
irrelevant, because such an invention should be regarded not so much
as a proposed _innovation_ in an old trade as the _creation_ of a new
one.

George Stephenson's ideas on the transport of passengers and goods
were almost unanimously condemned by the experts of his day who were
engaged in that line of business. On points relating to wheels of
waggons and the harness of horses, the opinions of these men were
probably worth something; but in relation to steam locomotives,
carriages and trucks running upon rails, their judgment was not merely
worthless, but a good deal worse; it was indeed actually misleading,
because based on a pretence of knowledge of a trade which was to be
called into existence to compete with their own. "Great is Diana of
the Ephesians" said the artificers of old; and on the strength of
their expert knowledge in the making of idols they set themselves up
as judges of systems of theology and morality. The argument, although
based on self-interest subjectively, was nevertheless intended to
carry weight even among persons who wished to judge the questions in
dispute according to their merits, and most of the latter were only
too ready to accept the implied dictum that men who work about a
temple must be experts in theology! The principles upon which Royal
Commissions and Select Committees are sometimes appointed and
entrusted with the onerous duty of deciding upon far-reaching
industrial problems, affecting the progress of trade and manufactures
in the present day, involve exactly the same kind of fallacy. Men are
selected to pronounce judgment upon the proposals of their rivals in
trade, and narrow-minded specialists to give their opinions upon
projects which essentially belong to the border lands between two or
more branches of industry, and cannot be understood by persons not
possessing a knowledge of both.

Yet the world's work goes on apace; and as capital is accumulated and
seeks to find new outlets the multiplication of industrial projects
must continue in spite of every discouragement. This process will go
on at a rate even faster than that which was exhibited at the
beginning of the nineteenth century; but in watching the course of
advancement, the world must take count of ideas rather than of the