The reversal of the bed was accomplished by a roller at either end of the bed entering a recess in a disc on the driving shaft, which in a half revolution brought the bed to a stop and started it in the opposite direction. This involved a new principle; a crank action operating directly upon the bed from a shaft having a fixed centre, and within recent years modifications of this patent have been successfully employed to drive the type bed at a high velocity and reverse it without shock or vibration. The “Miehle” Press is a modified form of this movement; the crank pin or roller is attached to the side of the bed wheel, and at the ends of the uniform movement it is enclosed within the walls of a vertical guideway formed at each end of the rack supporting frame, and passes through the length of this guide as it performs its function of reversing the bed. An improvement in this class of bed motions has lately been made and patented by Hoe & Co. In this machine the crank pin, which controls the reversal of the motion of the type bed, moves in a rectilinear instead of a circular pathway. As the motion of the crank is thus directly in line with the travel of the bed, it is possible to lock the journal box, enclosing the pin, securely to the bed, while the bed is being controlled by the action of the crank, and thereby avoids the friction and consequent wear of parts that occur when the crank pin moves in a circular line. The movement of the crank is obtained from the rotatory motion of the bed wheel, and has the same varying velocities as would be derived from a crank traveling in a circular pathway. It, therefore, checks the momentum of the bed with ease, brings the bed to rest, and returns it with an accelerating motion while under positive control. The wearing of parts is thus reduced to the minimum, insuring an accuracy of register and exactness of motion hitherto unattainable. A press with a bed measuring 48 × 65 inches runs without jar or vibration at a speed of 1,800 impressions an hour. The press of the present day from which the finest letterpress and woodcut work is turned off is known as the “Stop Cylinder.” This was devised and patented by a Frenchman named Dutartre, in 1852, and introduced into this country about 1853 by Hoe & Co., who have since patented many improvements upon it. It was a surprise to many printers to find that this machine could do work which heretofore it had been supposed the hand press only was capable of performing. [Illustration: STOP CYLINDER LITHOGRAPHIC PRESS]