Wireless Telegraphy (Apr. 18, 1899)

Prof. C. J. Lynde Gives a Practical Demonstration of It to Students.

Yesterday and to-day Prof. C. J. Lynde has been giving his classes a demonstration of the methods used in wireless telegraphy. Prof. Lynde constructed the apparatus during vacation and it consists of a complete transmitter and receiver. The demonstrations before the classes consisted of sending messages through space, through obstructions such as brick walls, of starting motors, lighting electric lights, and the exploding of gun powder.

Prof. Lynde gave a history of the steps leading up to the discovery of the wireless telegraphy.

In 1861 Faraday propounded the theory that heat, light and electricity are related and are all due to disturbances in the ether. Maxwell developed this theory mathematically. These electrical waves are generated wherever an electrical spark occurs. They travel in all directions unless they strike some metallic substance which will act as a reflector. In 1889 and following years Prof. Lodge, of Liverpool, perfected an apparatus for receiving these rays and using them to reproduce signals. Lodge can therefore rightly be called the father of wireless telegraphy. He, however, put the limit of the distance through which a message could be sent at half a mile. In 1897 Marconi, a young Italian, made a discovery that increased a hundred fold the distance through which a message could be sent. Using a Hertz transmitter and a Lodge receiver he discovered that by connecting one pole of each to the ground and the other pole of each to a wire running vertically into the air, the distance over which a message could be sent was greatly increased, the distance being proportional to the length of the vertical wire. Experiments have been going on for two years in England and they have succeeded in keeping up communication between points 18 and 20 miles distant for months at a time. During the last two weeks they have succeeded in opening up communication between France and England, a distance of 32 miles across the English channel. This apparatus tends to make a great change in wireless telegraphy. There are several other uses which have been suggested for this apparatus, such as communicating between battleships, between army and navy and between lighthouses and shore. One use that has been suggested is that all vessels carry both transmitter and receiver and in fogs the vessels could communicate with each other. The torpedo boat which Tesla claimed he had invented and which was to be run by electricity without leading wires was to be run on this principle.