Masters of SpaceAppendix A. New Developments of the Telegraph
The invention of Samuel F.B. Morse is unique in this, that the methods and instruments of telegraph operation as he evolved them from his first experimental apparatus were so simple, and yet so completely met the requirements, that they have continued in use to the present day in practically their original form. But this does not mean that there has not been the same constant striving for betterment in this as in every other art. Many minds have, since the birth of the telegraph, occupied themselves with the problem of devising improved means of telegraphic transmission. The results have varied according to the point of view from which the subject was approached, but all, directly or indirectly, sought the same goal (the obvious one, since speed is the essence of telegraphy), to find the best means of sending more messages over the wire in a given time. It will readily suggest itself that the solution of this problem lies either in an arrangement enabling the wire to carry more than one message at once, or in some apparatus capable of transmitting messages over the wire more rapidly than can be done by hand, or in a combination of both these principles. Duplex and quadruples operations are perhaps the most generally known methods by which increased utilization of the capacity of the line has been achieved. Duplex operation permits of the sending of two messages over one wire in opposite directions at the same time; and quadruples, the simultaneous transmission of four messages, two going in each direction. Truly a remarkable accomplishment; but, like many other things that have found their permanent place in daily use, become so familiar that we no longer pause to marvel at it. These expedients constitute a direct and very effective attack on the problem how to get more work out of the wire with the existing means of operation, and on account of their fundamental character and the important place which by reason thereof they have taken in the telegraphic art, are entitled to first mention. The problem of increasing the rapidity of transmission has been met by various automatic systems of telegraphy, so called because they embody the idea of mechanical transmission with resulting gain in speed and other advantages. The number of these which have from time to time been devised is considerable. Not all have proven to be practicable, but those which have failed to prove in under actual operating conditions none the less display evidence of ingenuity which may well excite our admiration. |