The idea of replacing the platen by a cylinder was not a new one. It was employed in printing copper-plate engravings in the fifteenth century, a stationary wooden roller being employed, beneath which the bed, with its form and paper, was moved backward and forward, a sheet being printed at each movement. With this idea began a new era in the evolution of the printing press. A vast number of patents have since been issued for printing machines in which the cylinder is connected with the bed and later for the operation of two cylinders together, one holding the form of type and the other making the impression. But all these were for improvements, the underlying principle remaining the same. The conception of a press of this character in which the paper was to be fed into the press in an endless roll or “web” goes back to the beginning of the nineteenth century, though it was not made available until a later date. [Illustration: CLYMER’S COLUMBIAN PRESS, 1816] Meanwhile, however, patent after patent for the improvement of the cylinder press were taken out and the art of printing improved rapidly, the firm of Hoe & Co. being one of the most active engaged in this business, the United States continuing in advance of Europe in the development of the art. The single small cylinder and double small cylinder introduced by this firm proved highly efficient, the output of the former reaching 2,000 impressions per hour, while the double type, used where more rapid work was needed, yielded 4,000 per hour. [Illustration: PETER SMITH HAND PRESS, 1822] But the demands of the newspaper world steadily grew and in 1846 a press known as the Hoe Type Revolving Machine was completed and placed in the office of the _Public Ledger_, of Philadelphia. By increasing the number of cylinders the product was rapidly added to, each cylinder printing on one side 2,000 sheets per hour. In 1835 Sir Rowland Hill suggested that a machine might be made that would print both sides of the sheet from a roll of paper in one operation. A similar double process had been performed for many years in the printing of cotton cloth. This remained, however, a mere suggestion until many years later, and the one-side printing continued. But, by adding to the number of cylinders, a speed of 20,000 papers thus printed was in time reached. [Illustration: TREADWELL’S WOODEN-FRAME BED AND PLATEN POWER PRESS, 1822]