As soon as the roll is finished, it is detached from the keyboard and introduced to the casting machine. Hitherto passive, it now becomes active. Having been placed in position on the rollers it is slowly unwound by the machinery. The paper passes over a hollow bar in which there are as many holes as there were punches in the keyboard, and in precisely the same position. When a hole in the paper comes over a hole in the hollow bar air rushes in, and passing through a tube actuates the type-setting machinery in a certain manner, so as to bring the desired die into contact with molten lead. The dies are, in the monotype, all carried in a magazine about three inches square, which moves backwards or forwards, to right or left, in obedience to orders from the perforated roll. The dies are arranged in exactly the same way as the keys on the keyboard. So that, supposing A to have been stamped on the roll, one of the perforations causes the magazine to slide one way, while the other shoves it another, until the combined motions bring the matrix engraved with the A underneath the small hole through which molten lead is forced. The letter is ejected and moves sideways through a narrow channel, pushing preceding letters before it, and the magazine is free for other movements. At the end of each word a “space” or blank lead is cast, its size exactly determined by the “justifying” hole belonging to that line. Word follows word till the line is complete; then a knife-like lever rises, and the type is propelled into the “galley.” Though a slave the casting machine will not tolerate injustice. Should the compositor have made a mistake, so that the line is too long or too short, automatic machinery at once comes into play, and slips the driving belt from the fixed to the loose pulley, thus stopping the machine till some one can attend to it. But if the punching has been correctly done, the machine will work away unattended till, a whole column of type having been set up, it comes to a standstill. The advantages of the Monotype are easily seen. In order to save money a man need not possess the complete apparatus. If he has the keyboard only he becomes to a certain extent his own compositor, able to set up the type, as it were by proxy, at any convenient time. He can give his undivided attention to the keyboard, stop work whenever he likes without keeping a casting-machine idle, and as soon as his roll is complete forward it to a central establishment where type is set. There a single man can superintend the completion of half-a-dozen men’s labours at the keyboard. That means a great reduction of expense.