[Illustration: TREADWELL’S WOODEN-FRAME BED AND PLATEN POWER PRESS, 1822]
To prevent the possible fall of types from a horizontal cylinder, the vertical cylinder was introduced by the London _Times_, but this danger was overcome in the Hoe presses, and by the subsequent invention of casting stereotype plates in a curve the final stage of perfection in design was reached. In 1865 William Bullock, of Philadelphia, constructed the first printing press capable of printing from a web or continuous roll of paper, knives being added to cut the sheets, which were then carried through the press by tapes or fingers and delivered by the aid of metal nippers. There were difficulties in this series of operations, but these were overcome in the later Hoe press, in which the sheets were merely perforated by the cutter, and were afterward fully separated by the pull of accelerating tapes.
The old-time rag-paper had disappeared for newspaper work, being superseded by wood-pulp paper, the cheapness of which added to the desire to produce presses of greater speed and efficiency. It was also desirable that papers should be delivered folded for the carrier, and this led to the invention of folding machines, one of the earliest of which, produced in 1875, folded 15,000 per hour.
We have in the foregoing pages told the main story of the evolution of the printing press from the crude machine used by Gutenberg in 1450 to the rapid cylinder press of four centuries later. There is little more to be said. Later changes were largely in the matter of increase of activity, by duplication and superduplication of presses until sextuple and octuple presses were produced, and by adding to the rapidity and perfection of their operation, and the extraordinary ingenuity and quickness with which the printed sheets were folded and made ready for the convenience of the reader. Sir Rowland Hill’s dream of a press which would print both sides of the paper at one operation in due time became a realized fact, while vast improvements in the matter of inking the forms, and even the addition of colored ink by which printing in color could be done, were among the new devices.
[Illustration: WASHINGTON HAND PRESS, 1827]