The life of George Stephenson, railway engineer - Lighthouse ...

138 LIFE OF GEORGE STEPHENSON. [chap. xii.
It was maintained by many that the results of these experiments
led to the greatest possible mechanical absurdities. For
example, it was insisted that, if friction was constant at all
velocities upon a level railway, when once a power was applied
to a carriage which exceeded the friction of that carriage by the
smallest possible amount, such excess of power, however small,
would be able to convey the carriage along a level railway at all
conceivable velocities. When this position was taken by those
who opposed the conclusions to which Mr. Stephenson had
arrived, he felt the greatest hesitation in maintaining his own
views ; for it appeared to him at first sight really the absurdity
which his opponents asserted it to be. Frequent and careful
repetition of his experiments, however, left no doubt upon his
mind as to the soundness of his conclusion,—that friction was
uniform at all velocities. Notwithstanding the ridicule that
was thrown upon his views by many persons with whom he
associated at the time, he continued to hold to this conclusion as
a fact positively established; and he soon afterwards boldly
maintained, that that which was an apparent absurdity was in-
deed an inevitable consequence, and that every increase of speed
involved a necessary expenditure of power almost in a direct
ratio.
It is unnecessary at this time of day to point out how obvious
this consequence is, and how it is limited and controlled by
various circumstances ; nevertheless it is undoubted, that could
you always be applying a power proportionately in excess of the
resistance, a constant increase of velocity would follow without
any limit. This is so obvious to professional men now, and is
indeed so axiomatic, that it is unnecessary further to illustrate
the position ; and the discussions which took place on the sub-
ject, when the results of Mr. Stephenson's experiments were
announced, are only here alluded to for the purpose of showing
the difficulties he had to contend with and overcome at the time,
and how small was the amount of science then blended with
engineering practice.*
* Some years afterwards, Mr. Sylvester, of Liverpool, published an able
pamphlet on this subject, in which he demonstrated, in a very simple and
beautiful manner, the correctness of Mr. Stephenson's conclusions.