The transmitter, Fig. 12, is interposed be tween the key and the magnetic coil. The former operates the magnet of the transmitter the object of which is to send uniform currents to the line, and also to short-circuit the phone, each ti me the coil battery circuit is broken, and thus obviate the annoyance which would otherwise be caused by the violent discharge close to the diaphragm.
In a small magnet, Fig. 13, is stored the en ergy which is exerted on the line for the purpose of operating the phones. As it is necessary to produce an instantaneous dis charge, a condenser is connected around the points of the transmitter, which makes and breaks the circuit around the coil.
The key, Fig. 14, is so constructed that when the lever is •• opened," or thrown to the right, it closes the circuit around the magnetic coil through the points of the transmitter, and when "closed," or thrown to the left. it opens this battery and at the same time short-circuits the magnetic coil. The necessity for this lies in the fact that an open-circuit electro poion battery of low resistance is employed, which tt is desirable to use only when occasion requires the transmission of signals, and also that the re sistance of the coil has an audible effect in the phone when it remains in the line to retard incom ing currents.
Thus, while the manipulation of the key accom plishes all the objects it is desirable to attain, it Introduces no innovation, as the same movements to which operators are accustomed are maintained—'• opening" for the transmission and "closing" for the reception of business.
A small resistance box, Fig. 15, is interpolated in such a way that when the current through the magnetic coil is broken on the up stroke it passes through the spools. This is to produce an audible distinction between the up and down movement as manifested in the phone, the former being lighter than the latter, so as to prevent confusion that otherwise would be occasioned by operators getting the " back-stroke.' The diagram.
Fig. 1G, shows all the instruments in place. All TIlorse keys and relays within the limits of a phonoplex circuit are bridged, as represented, by a condenser, through which pass the induced currents that operate the phones. It will be readily seen that the main line, which passes through the magnetic coil and through the phone, is never broken, the former being charged and discharged by means of an extra circuit around it through its key and the points of the transmitter.
The Cassagnes-11 i c h e la Steno-nlegraph. —Among the various methods of in creasing the number of words which can be transmitted over a telegraph line, is that in which stenography is called into play. invented by Miehela and perfected by Cassagues. The stenoglaf?hie s, stem employed subdivides words into their phonetic ele ments, which are repre sented graphically by vari ous conibinat ions of a very small number of different signs. The apparatus con sists of a key-board at one end of the lute and at the other a series of type levers, upon which the varhms st emigre Ode char acter:; are carried. By pressing a key at the send ing eml, the corresponding lever is raised at the re ceiving end, and the char acters are printed upon a roll of paper which ad vances a step after each imprint of one or more signs, according to the number of keys de pressed at, a ti MC. The mei hod cm iloyed being a phonetic one, it is applieable to any language.
The general arrangement of the receiving station is shown in Pig. 17. Each sector _If of the phonic wheel is connected with one of the polarized relays R.. etc., which close the circuits of the eleetro-magnets e e c through bat tery The printer P in Fig. 17 is shown in perspective in Fig. 1S, and consists of 20 printing levers which carry the stenographic signs. As each eleetro-magnet is energized it attracts its hinged armature from below and pushes up its printing lever. At the transmitting station the 20 keys on the hoard are connected to the sectors of the phonic wheel corresponding to those of the receiving station, so that the pressing of a key causes the corresponding sign to be printed. The polarized relay is shown in Fig. 19.
A stenographic line corresponds to the de pression of not more than 12 keys. The last of the relays is not connected to a printing eleetro, Nit to Ow electro-magnet if, Fig. 18. The movement of the armature of the latter effects the movement of the roll of paper, so that after every revolution of the phonic wheel the paper is advanced a step, on receiving its imprint of signs. After each movement the instrument is in condition to receive another impression.