That wireless telegraphy depends on disturbances of potential in the earth, regarded as an electrically charged sphere, rather than on Hertzian waves, as is usually supposed, is maintained by Rankin Kennedy. This physicist, says a writer in The Electrical Review (May 31), "has been unable to swallow or digest the usual statement that the workings of wireless telegraphy depend upon Hertzian waves, since he has been unable to see why such waves should be able to bend around the curved surface of the earth through many degrees of arc. ... In effect his suggestion is very plain. The earth may be regarded to all intents and purposes as an electrically charged sphere whose charge is at zero potential. If a disturbance is set up in this charge - which we are led to believe resides upon the surface of the earth - through the connection of an insulated capacity and a spark-gap with the earth, surges of current are caused to flow; then, inevitably, ripples of electrostatic disturbance will radiate out from the disturbing point, and these may be detected at great distances by means of appropriate apparatus sensitive to electric waves. It makes no manner of difference whether the sending and receiving circuits are parallel. A somewhat curious corollary of this hypothesis is that at the antipodal point from the sending-apparatus there ought to be a maximum of effect. If the earth were a smooth sphere having a uniformly disturbed charge, the ripples radiating away from the disturbing influence in widening concentric circles would come together again at the other end of the diameter of the sphere, where their mutual interference and addition would create a point of maximum effect. It would not be extremely difficult to test this assumption. If it is found true, the explanation of wireless telegraphy is evidently at hand. It may be remarked here that the antipodal point to Mr. Marconi's powerful sending-station in Cornwall is to be found in longitude 175 degrees east, and latitude 50 degrees 30 minutes south. This point is in the South Pacific Ocean, very near Auckland Island, which lies immediately to the south of New Zealand. There the British Government maintains an admiralty supply depot. It would be very interesting to know if messages which have faded out and become no longer sensible to the receiving instruments at 23 degrees away from the sending-station would not be again.easily received 180 degrees away at the antipodes. All that would be needed to try the experiment would be to send a ship provided with a receiving apparatus to the point indicated, and wait for results."