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Show WIRELESS. TELEGRAPHY. A Comprehensible Definition as to I What It Is. (Academy and Literature.) There is nothing very mysterious about it, and there is no reason why it should not be within the mental grasp of those most uninstructed in matters of science, bo long as they have sufficient imagination to comprehend the fundamental hypothesis on which all later theories of electricity ilre based. As is now well known to every intelligent, well informed person, between be-tween star and star, filling up a seemingly seem-ingly boundless void, and there is also between molecules of all substances, whether solid, liquid or aeriform, something which is vaguely known as ether. Of course, this something, this ether, cannot be handled it is not tangible: tan-gible: we can best infer it only from the fact that light, according to the latest scientific discoveries, is produced by extremely rapid vibrations in an elastic medium. It is by means of this ether, however, that we are now able to telegraph without wires. It was shown by Hertz that if sparks are allowed to pass between be-tween two conductors of a certain shape, electric oscillations are set up which extend to a considerable distance in all directions, The effect is, in fact, very like that produced in a pond when one throws a stone into it. It may seem, at first-sight, -as if the medium in which those oscillations are produced pro-duced might be the air. But if any object impermeable t-j air, such as the wall of a room or a house, is interposed in the path of such oscillations, they pass through it as if it were not there. There can, therefore, be no doubt that the medium of transmission is the ether, and that we cannot only transmit trans-mit signals through it in all directions, irrespective of intervening objects, but to almost any distance, provided we can only make the oscillations sufficiently suf-ficiently violent. The usual means of producing these oscillation-creating . sparks is the Ruhmkorff, or induction coil, whereby a rather feeble current of a voltaic cell or battery is-transformed into one of enormous intensity. It is possible to make coils that are capable of producing produc-ing oscillations that will extend for thousands of miles, but they are somewhat some-what impracticable, owing to techni-r cal difficulties'. . This, therefore.: .im? poses some limits Upon the use of wireless wire-less telegraphy. , This setting up of electric oscillations, oscilla-tions, or Hertzian waves, may be likened lik-ened to the waving of a flag by a signaler sig-naler anxious to attract the attention of a comrade on a distant height. 'In the latter case, however, the observer has his eyes to help him, while the Hertzian waves are not perceptible by our unaided senses. As they are given off every time that an induction coil, or the Wimshurst electric machine, or even one of the electric gas-lighters in common use, is - worked, it is evident evi-dent that they are passing through and around us; every day, without our being aware of the fact.' Something like an artificial eye is, necessary, therefore, to fulfill the same office as the telescope which the observer of flag signals calls to his aid when the dis-?: tance is too great for his unassisted vision. This first assumed practical shape in the "coherer' invented almost simultaneously simul-taneously by. Professor Branly of Paris and Principal Oliver Lodge. It consists of a glass tube filled with metal filings which, though they offer a strong resistance re-sistance to the passage of an electric current at ordinary times, have the singular property of becoming an excellent ex-cellent conductor when the Hertzian waves fall upon them, and of relapsing into their normal condition on receiving receiv-ing a light tap.! Signor Marconi conducted his earlier ear-lier experiments with his "coherer," but he now prefers to use a soft iron core surrounded by a coil of copper wire, near which a magnet is kept in constant con-stant revolution, by clockwork. The core is alternately magnetized and de magnetized, and a corresponding electric elec-tric current is set up in the surrounding surround-ing wire, of which one end is connected with the recording instrument and the other end in the earth. By the impinging im-pinging of a Hertzian wave upon the apparatus a slight extra impulse is occasioned, sufficient to set the recording record-ing instrument in operation. There remains to be said how it is possible to confine the ether waves sent out by the transmitting station to those instruments by which it i3 intended that they should be received. It is reported re-ported that an enterprising Frenchman, French-man, who set up his own wireless apparatus, ap-paratus, had become the unwitting recipient re-cipient of messages passing between warships of - the British northern squadron. There are many ways in which the problem may be overcome, and Principal Prin-cipal Oliver Lodge has shown that with apparatus so simple as' two parallel wires and a sliding ring connecting them, it is possible to "tune" an electric elec-tric circuit so accurately that it will omit sparks in sympathy with another one of exactly the same adjustment with which it is not in contact. The Italian navy claims to have overcome the same difficulty by the substitution of a globule of mercury between two carbon plugs for the recording instrument. instru-ment. Signor Marconi is employing somewhat different means for achieving achiev-ing the same result. There is ground to believe that, before be-fore a great while, the wireless system sys-tem will transmit human speeech over moderate distances, and replace our present clumsy telephoning methods completely. Scientists are now discussing dis-cussing the question whether ether may be utilized for the transmission of mechanical power, or of light. Wireless teleerraohv has brought us face to face with many new, almost romantic, problems by its use of ether as transmitting trans-mitting power. - |