Rensselaer Journal, Volume 11, Number 28, Rensselaer, Jasper County, 19 December 1901 — A MODERN MIRACLE IN MULTIPLE TELEGRAPHY [ARTICLE+ILLUSTRATION]

A MODERN MIRACLE IN MULTIPLE TELEGRAPHY

Along one of the ordinary post and telegraph lines between Paris and Bordeaux some extraordinary telegraphing has Just been accomplished. While the regular operators were sending and receiving back and forth their usual messages experimenting men of science had tapped the line, attached new instruments to it and were engaged in sending back and forth other messages of which the regular operators could not possibly have taken cognizance even had they been aware of their existence. The regular operators of the government service were using in one case a Morse duplex appa'ratus, which permits the (reversible) transmission of two simultaneous messages, and in the other a Baudot apparatus with four keyboards, which permits the sending of four messages in one direction. Bimply connecting their new apparatus with the'same wires, the experimenters succeeded in sending and receiving, simultaneously and In each direction, twelve other messages, making in all twenty-four simultaneous messages plus the two messages of the Morse duplex or the four messages of the Baudot apparatus. This was accomplished not only as a scientific novelty, but practically and continuously for hours at a time, in a test to establish the commercial usefulness of the invention. Tn this way it was demonstrated that the entire first page of a great newspaper, containing almost 9,000 words, can be sent from

Paris to Bordeaux along a single wire in one hour by means of the new invention simply, or by means of the new invention and a Baudot four-key-board apparatus working simultaneously in little more than a half hour, during which half hour the Bordeaux authorities may transmit to Paris by means of the new invention a text equivalent'to a halt, page of the same newsaper, always along the same solitary single circuit. Or should this seem less remarkable to Americans, habituated to the Wheatstone automatic device, than to Parisians, it may -be stated that 1,300 seperate and unprepared telegrams of twenty words each may be sent in a single hour over the single circuit by means of this wonderful invention. The inventor of the new system is Professor E. Mercadler, u .4l r ector of studies of the famous nique, the occupant of an impoHant chair in the Ecole Superieure des hMU tes et Telegraphes and chevalier of tW Legion of Honor. The actual transmitting device, as Professor Mercadler- showed and described it, consists essentially of what he has named electrodiapason inductophones, of which bfit three are shown in the. accompanying figure (Diagram No. 1). In place of three, the reader must suppose twelve, for the sending of the twelve simultaneous messages mentioned at the outset of the article. A diapason is a tuning fork, i. e., a forked piece of metal of such size and thickness that it vibrates invariably on a certain single tone. An electrodiapason Is one electrically maintained in a continuous vibratory movement, in the present case by means of an electro-magnet ("B,” Fig.

2) placed between the two forks, communicating on the one side with the pole of a small battery and on the other Bide with the tuning fork and with a steel stylus of necessary length fixed to one of the branches In front of a platinum plate communicating with the other pole of the battery. It it sufficient to put in contact the two poles for the electricity to act on the branches of the tuning fork (diapason), breaking the contact, which reestablishes itself when the branches return toward their primitive position, and so on continuously. A second stylus, or transmission stylus, is fixed to the second branch by a screw insulated from the tuning fork by a block of Ivory. This is put in communication by an insulated alluminum wire with the pole of another battery, or battery of transmission, of which the other pole is connected with a platinum plate by the Intermediary of qne of .the wires of an induction transformer. During the movement of the tuning fork (maintained as described), each time that the transmission stylus touches the connection with the battery the battery sends a current through the wire of the transformer. This wire is, then, traversed each second by a number of currents equal to the number of vibrations of the tuning fork. The result is an equal number of induction currents or vibrations in the wire No. 2 of the transformer, identical with those In the direct wire, from which the word

induetophone is given to the instrumonU. Now, at each end of the line (or disposed at different points along the line if desired) there are twelve of these electrically vibrating tuning forks (electrodiapasons), each tuned to |a note of the chromatic scale for an octave—do. re, mi, fa, sol, la, si—and the intervening half tones. The tuning fork No. 1, for example, is constructed so as to vibrate on the note of "si 3” and makes 480 vibrations per second. The tuning fork Not 2 is (say) tuned to "do 4” and makes 512 vibrations in the same time—and so on, from tuning fork to tuning fork, up to "la sharp 4,” which makes about 900 Vigrations a second. The actual apparatus is composed of a cylindrical box surrounded by a glass cover and containing an energetic magnet Whose c.ore is wound as in an ordinary telephone, but whose telephonic membrane (which is a metallic disk about two millimetres in thickness), instead of being fastened around Us circumference Is simply

posed, at three non-vibrating points on its surface, on metal stems fixed to rollers on a radius of a circular platform which supports them. Now, the diameter of each membrane.depends on the half-tone of its first harmonic—si 3 (480 vibrations per second), do 3 (512 Vibrations), do sharp 3 (543), and so on, from half-tone, to la sharp 4 (900 about), inclusively. Beach one of the membranes (thin metallic disks) is thus tuned exactly with one of the transmitting electro-diapasons (tuning forks) at the other end of the line.

PROF. MERCADIER