That tuned wireless telegraphy is, over moderate distances, at least as secret as that through wires (which can be tapped by induction) is evident from the fact that during the America Cup Yacht Races Mr. Marconi sent daily to the _New York Herald_ messages of 4000 total words, and kept them private in spite of all efforts to intercept them. He claims to have as many as 250 “tunes”; and, indeed, there seems to be no limit to their number, so that the would-be “tapper” is in the position of a man trying to open a letter-lock of which he does not know the cipher-word. He _may_ discover the right tune, but the chances are greatly against him. We may be certain that the rapid advance in wireless telegraphy will not proceed much further before syntonic messages can be transmitted over hundreds if not thousands of miles. It is hardly necessary to dwell upon the great prospect that the new telegraphy opens to mankind. The advantages arising out of a ready means of communication, freed from the shackles of expensive connecting wires and cables are, in the main, obvious enough. We have only to imagine all the present network of wires replaced or supplemented by ether-waves, which will be able to act between points (_e.g._ ships and ships, ships and land, moving and fixed objects generally) which cannot be connected by metallic circuits. Already ocean voyages are being shortened as regards the time during which passengers are out of contact with the doings of the world. The transatlantic journey has now a newsless period of but three days. Navies are being fitted out with instruments that may play as important a part as the big guns themselves in the next naval war. A great maritime nation like our own should be especially thankful that the day is not far distant when our great empire will be connected by invisible electric links that no enemy may discover and cut. The romantic side of wireless telegraphy has been admirably touched in some words uttered by Professor Ayrton in 1899, after the reading of a paper by Mr. Marconi before the Institution of Electrical Engineers. “If a person wished to call to a friend” (said the Professor), “he would use a loud electro-magnetic voice, audible only to him who had the electro-magnetic ear. “‘Where are you?’ he would say. “The reply would come--‘I am at the bottom of a coal mine,’ or ‘Crossing the Andes,’ or ‘In the middle of the Pacific.’ Or, perhaps, in spite of all the calling, no reply would come, and the person would then know his friend was dead. Let them think of what that meant; of the calling which went on every day from room to room of a house, and then imagine that calling extending from pole to pole; not a noisy babble, but a call audible to him who wanted to hear and absolutely silent to him who did not.” [Illustration: _Guglielmo Marconi._]