WIRELESS TELEGRAPHY. 



271 



with one vertical wire, and each set of apparatus select and respond 

 only to the particular rate of oscillations to which it is attuned. 



However, while the successful operation of contig-uous tuned cir- 

 cuits is quite within the possibilities, it is reported, as a result of 

 numerous tests in France and elsewhere, that freedom from inter- 

 ference with tuned apparatus is not yet secured. But if by the use of 

 tuned, apparatus nothing else were gained than the abilit}^, with a 

 given amount of electrical energy and a given height of vertical wire, 

 to transmit signals to a greater distance than is possil)le with untuned 

 apparatus, it imist be considered a decided advance in the art, and, 

 judging by the whole progress of electrical telegraphy, it is safe to 

 say, when so much has already been achieved, that the necessary 

 improvements to obtain at least practical freedom from interference 

 between adjacent apparatus will ultimately follow. 



The specimen of a dot and dash wireless telegraph record given in 

 Fig. 9 is a facsimile of bulletins ''caught on the wing'' during the 

 yacht races of 1899 in New York Harbor. Mr. Marconi had his 

 apparatus on the steamship I\»ict\ and was sending bulletins of the 

 progress of the race to the Mackey-Bennett cable ship, some miles 

 away, when this specimen and many others were recorded b}^ a set of 



S H 



R 



D 



RAW 



A W 



Fl<;. y. — Specimen of a dut imd dash wirok'ss tck'sraph rerord. 



Clarke wireless telegraph apparatus which the writer was siii)ervis- 

 ing on the steanishi]) Le Li randc l)nche><x!e. This was proljably the 

 Hrst instance of tapping Hertzian wave signals, in the United States 

 at least. It will ])e understood that Shr. is an ab])reviation for Shant- 

 rocl: Other al)breviations were used in these bulletins, as Col. for 

 (hlwinhia; abt. for al)out; l)d. for board, etc. The present si)eed of 

 signaling by wireless telegraphy when the tilings coherer is used, is 

 from 10 to 20 words per minute; but it seems reasonable to expect 

 that, with further improvements in the art, expert manipulators 

 of the key should eventually attain a considerably higher speed of 

 transmission. 



For practical purposes there is not much doubt that wireless teleg- 

 raphy will find its greatest tield of usefulness between vessels at sea, 

 or between vessels and the mainland, or between points divided by 

 the sea where it is not deemed feasible or profitable to lay a cable. 

 Numerous examples of such uses are already in evidence. There is, 

 for example, a wireless circuit between some of the Sandwich Islands; 

 another between the Lizard, Cornwall, and St. Catherines, Isle of 

 Wight, 186 miles apart, and between Poole and St. Catherines, 31 

 miles apart. The British Admiralty have also adopted the system for 

 many of their war ships and for some of their land stations. In all, 



