pressure
boiler for portable purposes, in which, to "expose a large surface to
the fire," he constructed the boiler of a number of small perpendicular
tubes "opening into a common reservoir at the top." In 1823 W. H. James
contrived a boiler composed of a series of annular wrought-iron tubes,
placed side by side and bolted together, so as to form by their union a
long cylindrical boiler, in the centre of which, at the end, the
fireplace was situated. The fire played round the tubes, which contained
the water. In 1826 James Neville took out a patent for a boiler with
vertical tubes surrounded by the water, through which the heated air of
the furnace passed, explaining also in his specification that the tubes
might be horizontal or inclined, according to circumstances. Mr.
Goldsworthy, the persevering adaptor of steam-carriages to travelling on
common roads, applied the tubular principle in the boiler of his engine,
in which the steam was generated _within_ the tubes; while the boiler
invented by Messrs. Summer and Ogle for their turnpike-road
steam-carriage consisted of a series of tubes placed vertically over the
furnace, through which the heated air passed before reaching the
chimney.

About the same time George Stephenson was trying the effect of
introducing small tubes in the boilers of his locomotives, with the
object of increasing their evaporative power. Thus, in 1829, he sent to
France two engines constructed at the Newcastle works for the Lyons and
St. Etienne Railway, in the boilers of which tubes were placed
containing water. The heating surface was thus considerably increased;
but the expedient was not successful, for the tubes, becoming furred
with deposit, shortly burned out and were removed. It was then that M.
Seguin, the engineer of the railway, pursuing the same idea, is said to
have adopted his plan of employing horizontal tubes through which the
heated air passed in streamlets, and for which he took out a French
patent.

In the meantime Mr. Henry Booth, secretary to the Liverpool and
Manchester Railway, whose attention had been directed to the subject on
the prize being offered for the best locomotive to work that line,
proposed the same method, which, unknown to him, Matthew Boulton had
employed but not patented, in 1780, and James Neville had patented, but
not employed, in 1826; and it was carried into effect by Robert
Stephenson in the construction of the "Rocket," which won the prize at
Rainhil