The daily morning journal and courier., 1899-12-28

III diameter, Which are placed apoul dI
 inch and one-half from two larger brass
 balls whose inner hemispheres, separa-
 ted from one another by the thirtieth
 of an inch, are inclosed In heavy rub
 Der tube filled with oil. To one of the
 small brass balls is attached a vertical
 conductor anywhere from twenty to
 two hundred feet in height depending
 on the distance it is desired to transmit
 a message, while the other small brass
 sphere is connected by means of a sim
 liar wire with the ground.
 | When the telegraph key in the pri-
 mary of the induction coil is closed an
 electric current flows through the cir l cult and creates a very great difference
 in electrical pressure in the secondary
 winding and thereby causes sparks to pass across between all four balls and
 through the oil bath. In other words,
 the action muc resembles discharge
 of lightning, only of course on minia- ture scale. These discharges create the electrical waves already referred to as having been discovered by Hertz, which oscillatio may be sent out into space In the form of long or short
 waves by holding down the telegra ph
 key for longer or shorter interval, In
 this way ordinary Morse teegraphic
 signals consisting of long and short
 strokes or dots and dashes are sent out
 in the form of electrical vibrations.
 Now, In order to receive these sig
 nals intelligently recourse is had to
 Branly's invention. This consists as
 already stated, of what is known as a
 coherer or a small glass tube about an
 inch and a half in length and one-thir-
 tieth of an inch internal diameter fitted with two plugs of silver to which pla-
 tinum wires are soldered, the remaining space in the tube being filled with mixture of nickel and silver filings. This sensitive tube Is connected in a
 circuit with an electric battery, high resistance telegraph relay, and sounder
 Under normal conditions the filings in the coherer will not allow of the pas- sage of the electric current from the To- cal battery but as soon as the electri- cal wave sent out from the transnitter strikes vertical wire similar to that on the sending instrument and con- nected with the tube, the filings, so to speak, weld themselves together or CO., here and allow the current to pass for longer or shorter interval depending on the length of the wave sent. This current in flowing around the circuit operates the relay and sounder and en- ables either dot or dash to be re- corded.
 It is found, however, that when the filings in the tube have responded to a wave from the transmitter they re- main welded together until such time as the tube has been struck a smart tap, when the filings loosen up or deco here and the tube returns again to it's state of high resistance.
 Now, in order to transmit Morse sig nals it is manifesty evident that some means have to be devised for tapping the tube automatically. For this pur- pose MT. Marconi makes use of little vibrating hammer attached to the sounder, which, after every wave, au- tomatlcally strikes the tube a sharp blow thus lossening the filings and permitting another wave to be recorded.
 With the apparatus described a speed of about twenty words a minute Is ob- tainable, and by employing in every case the high vertical wire which in- tensfies the wave effect and which Is original with MT. Marconi, the latter has gradually succeeded in increasing the distance over which intelibible can be sent from three miles in May. 1897. to over eighty miles in 1899.
 The principal defect In this system of telegraphy Is that as the electrical waves which emanate from the trans hitter when the key Is depressed radi- ate out into space in all directions they affect every receiver that lies within the area of their influence. Thus, for in- stance, were a message intended for Newark sent from New York, It would likewise be recorded at Poughkeepsie, New Haven and other points, assuming, If course, that receivers in proper ad- Iustment with the transmitter were placed In those cities. To overcome this difficulty, MT. Marconi it Is under stood Is at work upon reflector. by means of which he hopes to be able to | project the electric waves in an almost | parallel beam and in any desired direc- ion, in much the same way that the | avs of searchlight are focused. | How far this will prove effective re- mains to be proved by subsequent ex- lerments but it is safe to assert that before the Marconi system of tele- yraphy can be adopted on anything ike an extensive scale some scheme will have to be devised whereby a mes age intended for certain locality will )e recorded there, and there only.
 The question which naturally arises g, What future use will be made of his method of transmitting signals? That wireless telegraphy will ever re- ,lace the method of telegraphy now in general use for commercial purposes is scarcely likely, owing to the apparent y insurmountable defect Just referred o. On the other hand, such a system hould prove of great value in certain ases as, for instance, in communica- ing between lighthouses and the main- and, in warning vessel of the ap- roach of another during a fog in send ng dispatches between war vessels at ca. or in signaling from one army orps to another during a campaign, [ nd thus doing away with the necessity f running wires, William I.apidge in -lpct ricity