The steam engine familiarly explained and illustrated; with an historical sketch of its invention and progressive improvement; its applications to navigation and railways; with plain maxims for railway speculators. By the Rev. Dionysius Lardner ... With additions and notes by James Renwick ...

210 THE STEAM ENGINE.
by steam upon railroads; but the speed is considerably less,
nor, from the nature of the impelling power, is it possible
that it can be increased.
There is reason to suppose that a like effect takes place
with steam vessels. Upon increasing the power of the engines in some of the Post-office steam packets, it has been
found, that, while the time of performing the same voyage
is diminished, the consumption of fuel is also diminished.
Now since the consumption of fuel is in the direct ratio of
the moving power, and the latter in the direct ratio of the
resistance, it follows that the resistance must in this case be
likewise diminished.
(102.) When a very slow rate of travelling is considered,
the useful effects of horse-power applied on canals is somewhat greater than the effect of the same power applied on
railways; but at a?' speeds above three miles an hour, the
effect on railways is greater; and when the speed is considerable, the canal becomes wholly inapplicable, while the
railway loses none of its advantages. At three miles an
hour, the performance of a horse on a canal and a railway is
in the proportion of four to three to the advantage of the
canal; but at four miles an hour his performance on a railway has the advantage in very nearly the same proportion.
At six miles an hour, a horse will perform three times more
work on a railway than on a canal. At eight miles an hour,
he will perform nearly five times more work.
But the circumstance which, so far as respects passengers.
must give railways, as compared with canals, an advantage
which cannot be considered as less than fatal to the latter, is
the fact, that the great speed and cheapness of transit attainable upon a railway by the aid of steam-power will always
secure to such lines not only a monopoly of the travelling,
but will increase the actual amount of that source of profit in
an enormous proportion, as has been already made manifest
between Liverpool and Manchester. Before the opening of
the railway there were about twenty-five coaches daily run