WIEELESS TELEPHONY FESSENDEN. 187 



once made does not need to be altered."^ Of course, half the energy 

 is lost, but this is a matter of practically no importance, as the cutting 

 down of the strength of a telephonic conversation to one-half is as a 

 rule hardly noticeable, especially where there are no line noises or 

 distortion of the speech through capacity effects. 



Receiving station relay. — The receiving station relay is similar to 

 the transmitting relay shov»^n in plate 14, figure 1. The same remarks 

 apply to its use in connection with wire lines as to the transmitting 

 relay. 



OPERATION. 



As will be realized from the above, the operation of a wireless tele- 

 phone system is very simple. The ojDerator merely throws his switch 

 to the position for telephoning and talks into an ordinary transmitter 

 and listens in an ordinary telephone receiver. "Wlien the duplex 

 method is used, as is always advisable, the conversation proceeds 

 exactly as over an ordinary telephone line. Plate 20 shows a phono- 

 graph transmitting music and speech wirelessly. Plate 19, figure 3, 

 shows talking by relays from a local circuit. 



I believe I am correct in saying that the transmission by wireless 

 telephone is considerably more distinct than by wire line and that 

 the fine inflections of the voice are brought out much better. Tliis, 

 I presume, is due to the fact that there is no electrostatic capacity to 

 distort the speech, as in the case of wire lines, though I think the 

 effect is also partly due to the absence of telephone induction coils 

 with iron cores. Possibly some of the gentlemen present have wit- 

 nessed the operation of the wireless telephone transmission between 

 Brant Rock and Plymouth and between Brant Rock and Brookl}^!. 

 If so, I think they will bear me out in saying that the transmission 

 was clearer than over wire lines. 



As a rule, there is absolute silence in the wireless telephone receiver 

 except when talking is going on, though of course the usual noises 



<»Tliis method may, of course, be used for duplex working in wireless teleg- 

 raphy. As some question has been raised in regard to the capacity of wire- 

 less telegraph lines the writer would say that he has received messages at the 

 rate" of 250 words per minute by wireless and is now experimenting with 

 apparatus designed to give 500 woi-ds per minute. With duplexing this gives 

 1,000 words per minute or 60,000 words per hour. The manager of one of the 

 largest cable companies has stated (London Daily Mail, September 24, 1907) 

 that all the trans-Atlantic cables together send 24,000 words per hour. It 

 would appear, therefore, that if capacity alone be considered a single station 

 on each side of the Atlantic can handle more traffic than all the present cables. 

 It should be pointed out, however, that the mere ability to handle the messages 

 is not sufficient and that unless the wireless telegraph companies obtain land 

 facilities equal to those at present enjoyed by the cable companies they can not 

 handle the traffic as efficiently, i. e., can not deliver a message from New York 

 to an individual in London and receive a reply in the same time. Plate 19, 

 figure 2, shows a Wheatstoue transmitter used for the test referred to. 



