Each roller revolves upon an axis which is fixed. At the moment when the _form_ at the back of the machine is passing under the inking-roller, the sheet, which the boy has carefully laid upon the table before him, is caught in the web-roller and conveyed to the endless bands or tapes which pass it over the first impressing cylinder. It is here seized tightly by the bands, which fall between the pages and on the outer margin. The moment after the sheet is seized upon the first cylinder, the _form_ passes under that cylinder, and the paper being brought in contact with it receives an impression on one side. To give the impression on the other side the sheet is to be turned over, and this is effected by the two drums in the centre of the machine. The endless tapes never lose their grasp of the sheet, although they allow it to be reversed. While the impression has been given by the first cylinder, the second _form_ of types at the other end of the table has been inked. The drums have conveyed the sheet during this inking upon the second cylinder; it is brought in contact with the types, and the operation is complete. Koenig's machine, which was a very complicated instrument, was supplanted at the '_Times_' office by a modification of Applegath's and Cowper's machine, which printed four thousand sheets an hour on one side. But that has been superseded by a vertical machine, which prints ten thousand copies an hour, on one side. The separate columns of type are fixed on a large type-drum, two hundred inches in circumference. The drum is surrounded by eight impressing cylinders; the ink is applied to the surface of the type by rollers which work between these cylinders; and the sheets are laid on upon eight tables, (_h_, _h_, _h_,) which, by a most ingenious mechanism, carry each sheet to a point where its position is suddenly changed, and it is impressed between the type and the cylinder; the paper being then suspended by tapes, from which it is released as it passes forward, to be laid upon the heap which will be scattered, in a few hours, to every corner of the kingdom. [Illustration: Times Printing-Machine.] The printing machines, which have been in full operation for little more than twenty years, have called into action an amount of employment which was almost wholly unknown when knowledge was for the few. Paper-makers, type-founders, wood-engravers, bookbinders, booksellers, have been raised up by this extension of the art of printing, in numbers which far exceed those of any former period.