History of the Typewriter

—306— tank. Under the constant tension of the mainspring, the type-wheel tends to rotate in a. constant direction, but is controlled by the escapement wheel, which is operated by the magnet. The escapement is so arranged that a single pulsation of the magnet causes the type-wheel to rotate through the space of two letters. Thus, if the type-wheel is to be rotated through the space of six letters, there will be three pulsations of the magnet, three teeth of the escapement being allowed to pass. When this has occurred, the wheel is brought up in its approximate position, or midway between any two letters, and it is now necessary to move the type-wheel to the right or left just half a space, or 1-72 of a revolution, in order to bring the desired letter to the exact position of printing. The transverse motion of the type-wheel across the machine is accomplished by means of a cord which is attached at its centre to the type-wheel carriage, and extends parallel with the guide bar, passes over two small pulleys at the end of this bar, and is wound at each end on two drums. The drums are rotated by means of the ratchet wheel and the pawl at every pulsation of the magnet, each movement of the ratchet causing the type- wheel to travel transversely the space of one letter. The printing done by this most ingenious little machine is remarkably even, and in its spacing and general typo- graphical excellence it compares favourably with the best work that is turned out on the typewriter. The Murray Telegraphic System. An exceedingly interesting method of telegraphic typewriting has be en invented by Mr. Donald Murray, M.A., who uses as the base of his system the Bar-Lock typewriter. In the form in which it has reached its final development the method consists of a group of machines at each end of a telegraph wire. The message is perforated in a narrow paper tape, which is then run through an automatic transmitter, which, in its turn, sends signals over the wires corresponding to the holes in the paper tape. These signals are transmitted over the line at a speed sufficiently high to permit the transmission of the messages punched by several operators over one telegraph line. At the receiving station an electrical perforating mechanism under the control of the transmitted signals makes an exact reproduction of the transmitting tape. This received tape then runs into the automatic typewriter or “ printer,” which prints the messages in ordinary typewriting in page form under the control of the perforated receiving