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 ...

230 THE STEAM ENGINE.
have doubts upon this subject, if there be any such persons,
will be fully satisfied by referring to the evidence which accompanies the report of the committee of the House of Commons, printed in October, 1831. In that report they will
not-only find demonstrative evidence that the introduction
of steam carriages will materially contribute to the saving in
the-wear of turnpike roads, but also that the practicability
of working such carriages with a great saving to the publicwith great increase of speed and other conveniences to the
traveller-is fully established.
The weight of machinery necessary for steam carriages is
sometimes urged as an objection to their practical utility.
Mr. Gurney states, that, by successive improvements in,the details of the machinery, the weight of his carriages,
without losing any of the propelling power, may be reduced
to:35 cwt., exclusive of the load and fuel and water: but
thinks that it is possible to reduce the weight still further.
A steam carriage constructed by Mr. Gurney, weighing
35 cwt., working for 8 hours, is found, according to his
statement, to do the work of about 30 horses. He calculates that the weight of his propelling carriage, which would
be capable of drawing 18 persons, would be equal to the
weight of 4 horses; and the carriage in which these persons
would be drawn would have the same weight as a common
stage coach capable of carrying the same number of persons.
Thus the weight of the whole-the propelling carriage and'the carriage for passengers taken together-would be the
same with the weight of a common stage coach, with 4'horses inclusive.:(108.) There are two methods of applying locomotives
upon common roads to the transport of passengers or goods;
the one is by causing the locomotive to carry, and the other
to draw the load; and different projectors have adopted the
one and the other method. Each is attended with its advantages and disadvantages. If the same carriage transport the
engine and the load, the weight of the whole will be less:in