RECENT ADVANCES IN WIRELESS TELEGRAPHY. 



1S3 



if any of these offices should proceed to send a message, say, to Cork, 

 ■while this office is receiving another message from Crookhaven, it 

 would cause an interference Avhich would result in the confusion of 

 the two messages, thus rendering them unintelligible. Any message 

 sent on the line will affect all the instruments and can be read by all 

 the other telegraph office^ on the line; but certain rules and regula- 

 tions are laid down and adhered to by the operators in the employ of 

 the General Post-Office which make it impossible for one station to 

 interfere with the rest. It is obvious that these same rules are appli- 

 cable to every case in which a group of equally tuned wireless tele- 

 graph stations hapi^en to be in proximity to each other. 



Although in many instances untuned wireless telegraphy may 

 prove of great utility, it is, however, clear that so long as some method 

 of rendering stations completely indeioendent of one another was not 



Fig. 4. Fig. 5. 



devised, a very important and elTectual limit to the i)ractical utiliza- 

 tion of wireless telegraphy would 1)e imposed. 



The new method adopted by the author in 1898, of connecting a 

 proper form of oscillation transformer in conjunction Avith a con- 

 denser (fig. 4), so as to form a resonator tuned to respond best to 

 waves emitted by a given leng-th of vertical wire, was a step in the 

 right direction. This improvement was described by the author in 

 a discourse which he had the honor to deliver in the royal institution 

 in February, 1900. 



Apart, however, from these improvements introduced into the 

 receiving circuits, it had been for some time apparent that one diffi- 

 culty in the way of obtaining syntonic effects was caused by the 

 action of the transmitting wire. This straight rod or wire in which 

 electrical oscillations are set up, forms, as is well known, a very good 

 radiator or emitter of electric waves ; but at the same time in all such 



