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


 Explanation of the Method Devised by
 Marconi for Transmitting Messages
 Through Space.
 Almost exactly half a century after Morse in 1S44 startled the world by ticking off that apt message, What hath God wrought" a rumor spread in scientific circles that method of transmitting signals through space without wires had been discovered. l That this seemingly impossible feat could readily be accomplished was ul- tlmately proved beyond a doubt and was mainly due to the Investigations of Heinrich Hertz, a young German phy- | sicist, Hertz demonstrated about 1888 1 that an electric spark under certain | conditions produced electrical osclla- | tions or waves which travelled in all directions through space in much the same way that waves areNcreated in a 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 loose ly together in 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 de- monstrated to exist by Hertz
 With these two discoveries as a basis the present system of wireless tele- graphy has gradually been evolved, by devsng 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 MT. William Marconi, a young Italian scientist.
 MT. Marconi was born at Griffone near Bologna, on April 25, 1874 His mother was an English woman, and this probably accounts in some meas ure for the almost entire absence of for eign accent in his speech. Ever since the age of fourteen MT Marconi has been keenly interested in electricity,
 
 has been working on the problem of wireless telegraphy without intermis- sion. Most of his experimental work has been carried on in England since July, 1896. and it may be of interest to state that on his arrival in that coun- try he received a rather rude welcome by having his instruments broken up and destroyed by ignorant custom house officials who mistooS them for in- fernal machines.
 The creditable results so far ob- tained 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 signals are sent, or the transmit ter, as it is called, Is what is known as an in- ductiOn coil. This consists of a cyin- 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 the primary winding of the coil is connected with a number of | dry batteries, such as are employed for bell ringing purposes, and with ar or- | dinary Morse telegraph key, thus mak- ing complete electric circuit, while the