History of the Typewriter

—297— As the operator, in order to read these messages, will require to keep his eyes fixed upon the needle, it is clear that he will be under some disability in committing the message to paper. To avoid this, devices have been intro- duced which cause a small hammer to strike a kind of anvil, or gong, and the operator is thus able not only to devote his sole attention to transcribing the message as it is received, but he can read the sounds much more readily, and with far less liability to error than in the previous case. It will be perceived from this, that there are two distinct operations in sending a telegraphic message, namely, the act of transmitting, and act of receiving. Since the dura- tion of time required to transmit a signal from one end of the line to the other is infinitely small, the only limit to the speed of transmitting is the power of the operator to send the electric pulses from the one end, and that of the receiver to read them at the other. It is in connection with these two operations that the typewriter, or rather the principles upon which the typewriter is constructed, come into operation. The reader will understand that when the handle of the transmitter is moved to the right, the needle moves the same way, and is represented by the mark \ , whilst a left movement is shown by /, so that a movement, first to the left and then to the right represents a ; one to the right and three to the left means b ; right left, right left means c ; right left, left is d, and so on. If, in place of a movement to the left we use a dot, and instead of a right stroke we use a dash, we still have the same alphabet in another form, thus, . — a, — . . . b, . — . — is c, .-----is d, and so on. The Morse Receiver prints the messages received accord- ing to this dot and dash alphabet on a narrow strip of paper. This saves the labour of one attendant in reading the messages, but beyond this does not facilitate matters at all. To do this another device, called a puncher, is used. In this machine there are three keys. The operator works these keys, in precisely the same manner as though he were turning the handle of the dial instrument, a tap on the left hand key punching the equivalent of a dot in the narrow tape, and one on the right hand key acting similarly with the dash, whilst the middle key is used as a spacer, to carry the tape gradually onward. The tape, so perforated, is then sent through a trans- mitter, and is recorded by the automatic receiver, and transcribed in the usual way.