The "Sheffield whittle" is as old as the time of Edward III., as we know from the poet Chaucer. Sheffield is still the metropolis of steel. It is in the change of iron into steel by a due admixture of carbon--by hammering, by casting, by melting--that the natural powers of Sheffield, her water and her coal, have become of such value. Wherever there is a stream with a fall, there is the grinding-wheel at work: and in hundreds of workshops the nicer labour of the artificer is fashioning the steel into every instrument which the art of man can devise, from the scythe of the mower to the lancet of the surgeon. The machinery that made the steel has called into action the skill that makes the file-cutter. No machine can make a file. The file-cutter with a small hammer can cut notch after notch in a piece of softened steel, without a guide or gauge,--even to the number of a hundred notches in an inch. It is one out of many things in which skilled labour triumphs over the uniformity of operation which belongs to a machine. The cutting of files alone in Great Britain gives employment to more than six thousand persons. This is one of the many instances in which it is evident that the application of machinery to the arts calls into action an almost infinite variety of handicrafts. An ordinary workman can obtain a knife for the price of a few hours' labour. The causes are easily seen. Every part of the labour that can be done by machinery is so done. One turn of a wheel, one stroke of a steam-engine, one pinch of a pair of rollers, or one blow of a die, will do more in a second than a man could do in a month. One man, also, has but one thing to do in connexion with the machinery; and when the work of the hand succeeds to the work of the wheel or the roller, the one man, like the file-cutter, has still but one thing to do. In course of time he comes to do twenty times as much as if he were constantly shifting from one thing to another. The value of the work that a man does is not to be measured in all cases by the time and trouble that it cost him individually, but by the market value of what he produces; which value is determined, as far as labour is concerned, by the price paid for doing it in the best and most expeditious mode. And does not all this machinery, and this economy of labour, it may still be said, deprive many workmen of employment? No. By these means the iron trade gives bread to hundreds, where otherwise it would not have given bread to one. There are more hands employed at the iron-works than there would have been if there had been no machinery; because without machinery men could not produce iron cheap enough to be generally used.