The daily morning journal and courier., 1900-01-22
WIRELESS TELEGRAPHY.
4 CLE1R DESCRIPTION OF THE
 SYSTEM
And the Principles Which Make It
 Possible.

| Almost excatly half century after Morse, in 1844, started the world by ticking off that apt message: "What hath God wrought?" a runor spread in
 scientific circles that method of trans hitting signals through space without wires had been discovered. That ths
 seemingly impossible feat could readl- ly be accomplished was ultimately
 proved beyond a doubt, and was mainly
 due to the investigations of Heinrich
 Hertz, young German physicist.
 Hertz demonstrated about 1888 that an
 electric spark under certain conditions
 produced electrical oscillations or waves
 which travelled in all directions through
 space, in much the same way that
 waves are created in quiet pond by
 the throwing in of a stone radiate.
 A year or two later French scientist
 by the name of Branly working along
 the same line made the startling dis
 covery that metal filings packed loosely
 together in a glass tube and having
 normally very high electrical resist
 ance became conductors and readily al
 lowed an electric current to pass
 through them when they were struck
 by an electric wave such as was demon-
 strated to exist by Hertz.
 With these two discoveries as
 basis the present system of wireless
 telegraphy has gradually been evolved,
 by devsing means for controlling the
 electrical waves sent out from the
 transmitter and by so arranging the
 tube with metal filings as to cause it to
 faithfully respond to the blows from
 these same waves
 Of the various inventors who have
 been endeavoring to perfect wireless
 telegraphy apparatus, no other has proved so successful as William Marc oni, young Italian scientist.
 MT. Marconi was born at Griffone, near Bologna, on April 25, 1874 His mother was an Englishwoman, and this probably accounts in some measure for the almost entire absence of foreign ac- cent in his speech. Ever since the age of fourteen MT. Marconl has been keen ly interested in electricity, and during the past four or five years has been working on the problem of wireless tel egraphy without intermission. Most of his experimental work has been carried on in England since July. 1S96 and it may be of interest to state that on his arrival in that country he received a rather rude welcome by having his in- struments broken up and destroyed by ignorant customs house officials, who mistook them for internal machines.
 The creditable results so far obtained by MT. Marconi, both abroad and in this country, are unquestionably due to the apparatus of which he makes use. The device by means of which the sig nals are sent, or the transmitter, as 1t is called. is what is known as an in- ductlon coil. This consists of cylin- drical bundle of soft iron wires, upon which two separate coils of insulated wire are carefully wrapped. The first of these coils, of reasonably heavy wire and of one or two layers in depth only, is known as the primary" while the second wrapping, consisting of very many turns of fine wire, is called the secondary" In the Marconi transmit ter the primary winding of the coil is with a number of dry batter es, such as are employed for bell-ring- Ing purposes, and with an ordinary Morse telegraph key, thus making a 1 complete circuit, while the secondary | winding is connected to two brass balls | about an inch and one-half in diameter, | which are placed about an inch and | ,ne-half from two larger brass balls | whose inner hemispheres. separated | rom one another by the ttirtieth of an | nch, are inclosed in heavy rubber | ube filled with oil. To one of the small | )rass balls is attached vertical con- | luctor anywhere from twenty to two hundred feet in height, depending on he distance it is desired to transmit message, while the other small brass phere is connected by means of a sim lar wire with the ground.
 When the telegraph key in the pri- nary of the induction coll is closed an lectric current flows through the cir uit and creates very>sreat difference n electrical pressure in the secondary r winding and thereby causes sparks to ass across between al four balls and l trough the oil bath. In other words, he action much resembles a discharge f lightning, only of course on minia- ure scale. These discharges create the lectrical waves already referred to as aving been discovered by Hertz which scillations may be sent out into space l the form of long or short waves by olding down the telegraph key for ,nger or shorter interval. In this way rdinary Morse telegraphic signals con- lsting of long and short strokes or ots and dashes are sent out in the )rm of electrical vibrations.
 Now, in order to receive these sig als intelligently recourse is had to ranly's invention. This consists, as \ ready stated, of what is known as a 1herer or 8 small glass tube about an lch and half in length and one-thir- eth of an inch internal diameter fitted ith two plugs of silver to which pla- mum wires are soldered, the remaining pace in the tube being filled with a
 fixture of nickel and silver filings. his sensitive tube is connected in a 'rcuit with an electric battery, high 'sistance telegraph relay and sounder Under normal conditions the filings in se coherer will not allow of the pas ge of the electric current from the To- Il battery, but as soon IS the electrical ave sent out from the transmitter rikes vertical wire similar to that l the sending instrument and connect l with the tube, the filings, 50 to 'eak, weld themselves together or CO., gre and allow the current to pass for ' longer or shorter interval repending the length of the wave sent. This
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