The invention of wireless telegraphy brought about a curious problem in espionage during the Russo-Japanese War. A steamer, fitted with a wireless installation, followed the movements of the rival fleets in the interests of one of the London papers. She was boarded by a Russian cruiser, and, as result, the Russian Government informed the neutral Powers that should any neutral vessel be found within the Russian maritime zone, having on board correspondents with apparatus of this kind--which, obviously, was not foreseen in the then existing Conventions--used for the purpose of transmitting information to the enemy, the correspondents would be treated as spies, and the vessels made prizes of war. That position is now untenable. Owing to the improvements made in wireless telegraphy, a very similar situation might arise in a land war. It is possible, to-day, to carry in an ordinary motor-car a wireless outfit capable of sending messages a very considerable distance; indeed, there is good reason for believing that such an apparatus is actually being used by German agents for transmitting information from the east and north-east districts of England, to enemy submarines lurking in the North Sea. A rigorous search has been made for this mysterious car, which has been reported in various districts. Naturally, when the apparatus is not in use it is concealed within the body of the car, which would then become, apparently, an ordinary touring vehicle, with nothing to distinguish it from hundreds of others passing freely along the roads. In this case there would be little doubt about the fate of the occupants of the car if they were caught. They would not be "spies" in the strict sense of the word, as their offence was not committed within the zone of the operations, but they would be guilty of "war treason," and liable to the death penalty. This is a very real danger, and the offence is one that it would be extremely difficult to detect. The popular idea of a wireless plant, gained no doubt from the enormous "aerials" of the high-power stations sending messages thousands of miles, is that wireless telegraphy is something that cannot be carried on without employing huge plant that it would be impossible to conceal. Now I can claim to know something of wireless telegraphy--I have experimented for some years--and I can say, at once, that this is an exceedingly dangerous fallacy. In recent years very great improvements have been made in both transmitters and receivers, and to-day it is quite possible to establish in almost any house, a small, but powerful wireless plant, which would be utterly invisible from outside, but quite capable of sending messages from any spot near the coast to enemy vessels, such as submarines, lying a few miles away.