French Wireless Telegraphy

Messages Sent Two and a Half Miles in Paris with Atmosphere as Only Conductor.

WASHINGTON, D. C., Sunday. — A report on the French development of wireless telegraphy since the discovery of the Hertz waves in 1889 is submitted to the State Department by Commercial Agent Atwell, in Roubaix.

M. Ducretet, in Paris, has in successful operation a wireless telegraphic plant sending messages nearly two and a half miles. His system depends on a special radio-conductor, known in this country as the Branly tube, which replaces the soft iron magnet of an ordinary telegraphic instrument. The special receiver is connected with an ordinary Morse sounder and operated with no other conductor than the atmosphere.

M. Ducretet's sending station has a mast sixty-five feet high above the roof of his laboratory to start the current above the interference of surrounding buildings, as the electric waves will pass through an ordinary wall, but are deflected by iron structures.

M. Ducretet says the British government has been experimenting with a practically identical apparatus, and has sent messages between Bournemouth and the Isle of Wight. He says his experiments do not indicate that Hertz telegraphy will soon displace ordinary wire lines, but have already been demonstrated of practical value for lighthouses, naval signals and like uses. He further says that with his machine incandescent lamps may be lighted at a distance or mine charges exploded, it being only a question of obtaining sufficient power.

With the retirement of Mr. Roosevelt the Navy Department dropped negotiations for wireless telegraphy from war ships which it had under consideration, as proposed by Tesla.