li)ll] on Ra(li()frl'>f/ra/)hi/. 2()*.) 



200 to 28,000 feet, and moreover that wave group tuning and direc- 

 tive systems are now available, it is not difficult to foresee that this 

 comparatively new method of communication is destined to fill a 

 position of the greatest importance in facilitating communi(!atiou 

 throughout the world. 



Apart from long-distance work, the practical value of wireless 

 telegraphy may perhaps be divided into two parts : (1) when used 

 for transmission over sea ; (2) when used over land. 



Many countries, including Italy, Canada and Spain, have already 

 supplemented their ordinary telegraph systems by wireless telegraphy 

 installations, but some time must pass before this method of commu- 

 nication will be very largely used for inland purposes in Europe 

 generally, owing to the efficient network of landlines already existing 

 which render further means of communication unnecessary ; and 

 therefoi'e it is probable that, at any rate for the present, the main use 

 of radiotelegraphy will be confined to extra-European countries, in 

 some of which climatic conditions and other causes absolutely pro- 

 hibit the efficient maintenance of landline telegraphy. A proof of 

 this has been afforded by the success which has attended the working 

 of the stations recently erected in Brazil on the Upper Amazon. 



By the majority of people the most marvellous side of wireless 

 telegraphy is perhaps considered to be its use at sea. Up to the 

 time of its introduction, ships at any appreciable distance from land 

 had no means of getting in touch with the shore throughout the 

 whole duration of their voyage. But those who now make long sea 

 journeys are no longer cut ofp from the rest of the world ; business 

 men can continue to corres]iond at reasonable rates with their offices 

 in America or Europe ; ordinary social messages can be exchanged 

 between passengers and their friends on shore ; a daily newspaper is 

 published on board most of the principal liners, giving the chief news 

 of the day. Wireless telegraphy has on more than one occasion 

 proved an invaluable aid to the course of justice — a well known 

 instance of which is the arrest, which took place recently through its 

 agency, of a notorious criminal when about to land in Canada. 



The chief ])enefit, however, of radiotelegraphy lies in the facility 

 which it affords to ships in distress of communicating their plight to 

 neighbouring vessels or coast stations ; that it is now considered 

 indispensable for this reason is shown liy the fact that several govern- 

 ments have passed a law making a wireless telegraph installation a 

 compulsory part of the equipment of all passenger boats entering 

 their ports. 



[0. M.] 



Vol. XX. (Xo. 105) 



