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 ...

1.90 THE STEAM -ENGINE.
various circumstances assumed by Messrs. Walker and
Rastrick, in making their estimate, with those under which
the transport was actually effected. The first point of difference which he observed was the speed of transport: the
estimate was founded on an assumed speed of ten miles an
hour, and it was stated that a four-fold speed would require
an:addition of 50 per cent. to the power, without taking into
account wear and tear. Now the actual speed of transport
being double the speed assumed in the statement, Mr. Booth
holds it to be necessary to add 25 per cent. on that score.
The next point of difference is in the amount of the loads:'
the estimate is founded upon the assumption, that every
engine shall start with its full complement of load, and that
with this it shall go the whole distance. "The facts, however, are," says Mr. Booth, "that, instead of a full load of
profitable carriage frown Manchester, about half the wagons
come back empty, and, instead of the tonnage being conveyed
the whole way, many thousand tons are conveyed only
half the way; also, instead of the daily work being uniform,
it is extremely fluctuating." It is further remarked, that in
order to accomplish the transport of goods from the branches
and from intermediate places, engines are despatched several
times a day, from both ends of the line, to clear the road;
the object of this arrangement being rather to lay the foundation of a beneficial intercourse in future, than with a view
to any immediate profit. Mr. Booth makes a rough estimate of the disadvantages arising from these circumstances
by stating them at 33 per cent. in addition to the original
estimate.
The next point of difference is the fuel. In the original
estimate coal is assumed as the fuel, and it is taken at the
price of five shillings and tenpence per ton: now the act of
Parliament forbids the use of coal which would produce
smoke; the company have, therefore, been obliged to use
coke, at seventeen shillings and sixpence a ton. Talking