ridge, and Mr. Kennedy, of Manchester.

It was now felt that the fate of railways in a great measure depended
upon the issue of this appeal to the mechanical genius of England. When
the advertisement of the prize for the best locomotive was published,
scientific men began more particularly to direct their attention to the
new power which was thus struggling into existence. In the meantime
public opinion on the subject of railway working remained suspended, and
the progress of the undertaking was watched with intense interest.

During the progress of this important controversy with reference to the
kind of power to be employed in working the railway, George Stephenson
was in constant communication with his son Robert, who made frequent
visits to Liverpool for the purpose of assisting his father in the
preparation of his reports to the board on the subject. Mr. Swanwick
remembers the vivid interest of the evening discussions which then took
place between father and son as to the best mode of increasing the
powers and perfecting the mechanism of the locomotive. He wondered at
their quick perception and rapid judgment on each other's suggestions;
at the mechanical difficulties which they anticipated and provided for
in the practical arrangement of the machine; and he speaks of these
evenings as most interesting displays of two actively ingenious and able
minds stimulating each other to feats of mechanical invention, by which
it was ordained that the locomotive engine should become what it now is.
These discussions became more frequent, and still more interesting,
after the public prize had been offered for the best locomotive by the
directors of the railway, and the working plans of the engine which they
proposed to construct had to be settled.

One of the most important considerations in the new engine was the
arrangement of the boiler, and the extension of its heating surface to
enable steam enough to be raised rapidly and continuously for the
purpose of maintaining high rates of speed--the effect of high pressure
engines being ascertained to depend mainly upon the quantity of steam
which the boiler can generate, and upon its degree of elasticity when
produced. The quantity of steam so generated, it will be obvious, must
chiefly depend upon the quantity of fuel consumed in the furnace, and,
by necessary consequence, upon the high rate of temperature maintained
there.

It will be remembered that in Stephenson's first Ki