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 plates independent of the refractory men, and the work was executed with a despatch, accuracy, and excellence that would not otherwise have been possible. Only a few years since Mr. Roberts added a useful companion to the Jacquard punching machine, in his combined self-acting machine for shearing iron and punching both webs of angle or T iron simultaneously to any required pitch; though this machine, like others which have proceeded from his fertile brain, is ahead even of this fast-manufacturing age, and has not yet come into general use, but is certain to do so before many years have elapsed.