1905.] on Recent Advances in Wireless Telegraphy. 



33 



line there are a dozen or more telegraph offices, all with their instru- 

 ments joined up to the same wire running from the terminal stations. 

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

 Cork, whilst this office is receiving another message from Crookhaven, 

 it would cause an interference which would result in the confusion of 

 the two messages, thus rendering them unintelligible. Any message 

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

 the other telegraph offices 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 

 applicable to every case in which a group of equally tuned wireless 

 telegraph stations happen 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 independent of one another 

 was not devised, a very important and effectual limit to the practical 

 utilisation of wireless telegraphy would be imposed. 

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

 a proper form of oscillation transformer in conjunction with a con- 

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



Fig. 4. 



waves emitted by a given length of vertical wire, was a step in the 

 right direction. This improvement was described by the author in a 

 discourse which he had the honour 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 

 Vol. XVIII. (No. 99) d 



