more than $2,750.

8. The boiler must stand a pressure, when tested, of 150 pounds per
square inch.

9. It must be ready for trial October 1, 1829.

The publication of these conditions and the offer of the prize
excited great interest, and caused no small amount of comment.[11]
The Stephensons at once began the construction of "The Rocket,"
without doubt the most famous locomotive ever built. The improved
feature it was to have was increased heating surface, so that
without increased weight it could generate more steam. This was
effected by putting fire-tubes through the water in the boiler.
Boiler-tubes had already been used by different people, and some of
Stephenson's locomotives which he had sent to France had been fitted
with tubes. At the suggestion of Mr. James Booth, Stephenson decided
to use a large number of tubes. Modern boilers have smaller tubes
and more of them, but "The Rocket" was the first to typify the
modern multitubular boiler. In other respects "The Rocket" was like
Stephenson's other locomotives built ten or twelve years earlier.

[Footnote 11: It is said that a prominent man of Liverpool
declared that "only a parcel of charlatans would ever have
issued such a set of conditions; that it had been _proved_ to
be impossible to make a locomotive go ten miles per hour." He
added that, "if it ever was done, he would eat a stewed
engine-wheel for breakfast."]

A brief description of "The Rocket" will not be out of place: The
boiler was 6 feet long, 3 feet 4 inches in diameter, and was
furnished with 25 copper tubes 3 inches in diameter. The fire-box
was at the rear end of the boiler, 2 feet wide and 3 feet high,
surrounded by water. The cylinders were high on the sides, pointing
down to the forward wheels, which were the only drivers. Stephenson
had used coupling rods between two sets of "drivers," but "The
Rocket" was made for speed chiefly. Its weight when furnished with
water was only _four and a half tons_! On trial at Killingworth "The
Rocket" worked finely and its capacity for steam was marvellous. It
was sent by wagon to Carlisle and by boat to Liverpool.

On the day set for the trial there were four engines on hand: 1. The
"Novelty," built by young Ericsson, who afterward in New York built
the famous "Monitor." 2. The "Sanspareil," by Timothy Hackworth. 3.
The "Perseverance," by a Mr. Burstall. 4. "The Rocket," by
Stephenson and Booth.