Wireless telephony has been used with considerable success in various German collieries, and at the Dinnington Main Colliery, Yorkshire. Early last year Marconi succeeded in establishing communication by wireless telephony between Bournemouth and Chelmsford, which are about 100 miles apart; and about the same time a song sung at Laeken, in Belgium, was heard clearly at the Eiffel Tower, Paris, a distance of 225 miles. The German Telefunken Company have communicated by wireless telephony between Berlin and Vienna, 375 miles, and speech has been transmitted from Rome to Tripoli, a total distance of more than 600 miles. These distances are of course comparatively small, but if the microphone trouble can be overcome satisfactorily, transatlantic wireless telephony appears to be quite possible. CHAPTER XXI WIRELESS TELEGRAPHY--PRACTICAL APPLICATIONS A fairly good idea of the principles and apparatus of wireless telegraphy should have been gained in reading Chapter XX., but so far little has been said about its practical use. If we leave their power out of consideration, wireless stations may be divided into two classes: fixed stations on land, and moving stations, if the expression may be allowed, on ships. For moving stations wireless telegraphy has the field all to itself, but for communication between fixed stations it comes into conflict with ordinary telegraphy by wire or cable. As regards land messages over comparatively short distances, say throughout Great Britain, wireless telegraphy has no advantages over the older methods; and it is extremely unlikely that it ever will be substituted for the existing cable telegraphy. For long distances overland wireless has the great advantage of having all its apparatus concentrated at two points. A long land line passing through wild country, and exposed to all kinds of weather, requires constant labour to keep it in good repair, and when a breakdown occurs at any point, the repairing gang may be miles away, so that delay is caused. On the other hand, whatever may go wrong at a wireless station, no time is lost in effecting the necessary repairs, for everything is on the spot. At present there is no great competition between wireless and ordinary telegraphy for overland messages of any kind, but the case is different when we come to communication across seas and oceans. Already the cable companies have been affected considerably, and there is little doubt that they will feel the competition much more seriously before long. The general public, always conservative in such matters, have not yet grasped the fact that telegrams can be handed in at any telegraph office in the British Isles, and at most telegraph offices in the United States and Canada, for wireless transmission across the Atlantic, via the Marconi stations at Clifden and Glace Bay. The cost is remarkably small, being eightpence a word for ordinary messages.