driving-wheels
of the locomotive, at all times in the exact proportions required when
turning to the right or left,--an arrangement which has since been
adopted in many road locomotives and agricultural engines. In the same
patent will be found embodied his invention of the steam-brake, which
was also a favourite idea of George Stephenson, since elaborated by Mr.
MacConnell of the London and North-Western Railway. In 1834, Sharp,
Roberts, and Co. began the manufacture of locomotives on a large scale;
and the compactness of their engines, the excellence of their
workmanship, and the numerous original improvements introduced in them,
speedily secured for the engines of the Atlas firm a high reputation
and a very large demand. Among Mr. Roberts's improvements may be
mentioned his method of manufacturing the crank axle, of welding the
rim and tyres of the wheels, and his arrangement and form of the
wrought-iron framing and axle-guards. His system of templets and
gauges, by means of which every part of an engine or tender
corresponded with that of every other engine or tender of the same
class, was as great an improvement as Maudslay's system of uniformity
of parts in other descriptions of machinery.

In connection with the subject of railways, we may allude in passing to
Mr. Roberts's invention of the Jacquard punching machine--a self-acting
tool of great power, used for punching any required number of holes, of
any pitch and to any pattern, with mathematical accuracy, in bridge or
boiler plates. The origin of this invention was somewhat similar to
that of the self-acting mule. The contractors for the Conway Tubular
Bridge while under construction, in 1848, were greatly hampered by
combinations amongst the workmen, and they despaired of being able to
finish the girders within the time specified in the contract. The
punching of the iron plates by hand was a tedious and expensive as well
as an inaccurate process; and the work was proceeding so slowly that
the contractors found it absolutely necessary to adopt some new method
of punching if they were to finish the work in time. In their
emergency they appealed to Mr. Roberts, and endeavoured to persuade him
to take the matter up. He at length consented to do so, and evolved
the machine in question during his evening's leisure--for the most part
while quietly sipping his tea. The machine was produced, the
contractors were enabled to proceed with the punching of the p