A MARCONI DISCIPLE.

Gisborne Times, Volume XXVI, Issue 2376, 17 December 1908, Page 2

A MARCONI DISCIPLE.

WIRELESS TELEGRAPHY. A TEACHER’S INVENTION. A visitor to the Lawrence District High School would be struck on entering the school grounds with a novel •sight, in the shape of -a series of wires -stretched from two towering fir trees to the school buildings, _ a distance of about 40 yards. An investigation proves that the science of wireless ' telegraphy has laid hold of another enthusiast in Mr. J. E. Strachan, one of the teachers of the school, and with the assistance of -a friend (Mr. W. Eyes), his labors in that field have been carried on so successfully as to have installed a crude though workable station for the reception of wireless messages. Already messages have been received from temporary stations set up at various points in the district, and while the Dunedin messages are yet imperfect of reception, the prophecy is made that before-the year closes perfect - accord will exist between Dunedin and Lawrence, and messages will then come through in good order. The- sending apparatus consists of a -six inch spark coil fed by a battery of storage cells, and including in its primary circuit a telegraph-sending key and -a motor mercury break. When the key is operated the rapid series of sparks is broken up into dots and dashes, according to the Morse code, and appear between terminals of the coil. These terminals being connected to an air wire -and to earth, set up in the ether the- oscillatory disturbances now familiar as Hertzian waves, and these are propagated in all directions. Some idea of the speed -at which these waves travel may be got from the that they would be in Auckland in less than the 300th part of a second. In the receiving circuit the chief item is a detector, which consists meantime of a slip of -aluminium foil lightly poised across two -carbon knife edges. This is connected with a telephone receiver in which signals from a distant station can bo recognised in a series'of burrs of longer or shorter duration. Another

detector, less delicate in -action, -selves to operate the call bell. One of _ the advantages or disadvantages is tnat the bell will continue ringing until the operator attends it. Tuning is accomplished by adjusting induction coils and conclensors at each end. lhe air and earth wires are, meantime, connected direct to the instruments, but . the experimentors propose introducing transformers for high frequency oscillations in the sending and receiving circuits. All the apparatus, including the induction coil,, lias been made by the experimenters.