Wireless Telegraphy Apparatus.
Electric waves have long been harnessed by the use of wires for sending communications to a distance, but the ether exists outside of the wire as well as within; therefore, having the ether everywhere, it must be possible to produce waves in it which will pass anywhere on the earth’s surface, and if these waves can be controlled, messages can be transmitted as easily and certainly as the ether within the guiding wire. The problem lay in producing suitable instruments to effect this result. Marconi adopted a device invented by an Italian named Calzecchi, and improved by a Frenchman, Mr. Branley, called the coherer, which he greatly improved. This instrument is merely a small tube of glass about as big around as a lead pencil and two inches in length; this is plugged at each end with silver. The plugs almost touching within the tube, the narrow space between is filled with finely powdered particles of nickel and silver, which possess the property of being alternately good and very bad conductors of an electric current or waves. The waves that come from the transmitter, perhaps a thousand or two thousand miles away, are received, but are so weak that they could not of themselves actuate any ordinary telegraph instrument; they do, however, possess strength enough to draw the little fragments of silver and nickel in the coherer together in a continuous path; in other words, they make these metal filings cohere, and the moment they cohere they become a good conductor for electricity, and a current from a local battery operates the Morse instruments. Then a little tapper actuated by the same current strikes against the coherer, the particles of metal are separated or decohered, becoming instantly a poor conductor and thus stopping the current from the home battery; another wave comes through space into the coherer there drawing the particles again together and another dot or dash is printed. All these processes are continued rapidly until a complete message is received.
The sending instrument, or transmitter, is called the oscillator, a device somewhat similar to the familiar Morse telegraph key.
Marconi is now employed in perfecting an instrument by which the station only with which communication is desired can hear the signal, and receive the message. Thus the required secrecy will be preserved.
Marconi has patented over a hundred devices in connection with wireless telegraphy, but the nature and application of these has not been given to the public as yet.
Thomas A. Edison’s Opinion of Wireless Telegraphy.
“There is absolutely no reason why Marconi may not develop a speed of 500 words a minute in the transmission of translantic messages,” said Thomas A. Edison in course of an interview; “on the other hand,” continued the inventor, “there are technical, scientific and mechanical obstacles which make it absolutely impossible to increase the speed of transmission of ocean cables.
“There is not the least doubt but that the Marconi system is successful. All this talk about lack of secrecy and interception of messages is nonsense. At least ten men know the contents of every cable message, and none of them receive very high salary. Personally I have no doubt whatever that the Marconi system is both a commercial and scientific success.”