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

CHAP. IX.] INVENTION OF THE STEAM BLAST. 95
draught,
furnace.
and consequently the intensity of combustion in the
The experiment was no sooner made than the power of the
engine was at once more than doubled: combustion was stim-
ulated by the blast ; consequently the capability of the boiler to
generate steam was greatly increased, and the effective power of
the engine augmented in precisely the same proportion, without
in any way adding to its weight.
This simple but beautiful expedient, though it has hitherto
received but slight notice as an original idea on the part of its
author, was really fraught with the most important consequences
to railway communication ; and it is not too much to say that
the success of the locomotive depended upon its adoption. With-
out the steam blast, the advantages of the "multitubular
boiler " could never have been fairly tested ; and it was these
two improvements, working together, which afterwards secured
the triumph of the locomotive on the opening of the Liverpool
and Manchester Railway. Without the steam blast, by which
the intensity of combustion was kept up to the highest point,
and the evolution of steam thus rapidly effected, high rates of
speed by means of the combustion of coke could not have been
attained, and locomotives might still have been dragging them-
selves unwieldily along at little more than five or six miles an
hour.
The steam blast had scarcely been adopted, with so decided
a success, when Mr. Stephenson, observing the numerous defects
in his engine, and profiting by the experience which he had al-
ready acquired, determined to construct a second engine, in which
to embody his improvements in their best form. Careful and
cautious observation of the working of his locomotive had con-
pipe with its end turned upwards, the velocity of the current would be accelerated
; and such was the effect." (Practical Treatise on Railroads, by Nicholas
Wood, C.E. Ed. 1825, p. 292.) This passage clearly shows the preconceived"
design and purpose of Mr. Stephenson in inventing the steam blast. A claim
has, nevertheless, been set up in behalf of Timothy Hackworth, as its inventor
in 1829, although the design,' mechanism, and rationale of the invention, as ef-
fected hy Mr. Stephenson in 1815, and adopted by him in all the Killingworth
engines from that year downwards, were clearly described by Mr. Wood in
1825!