USE OF ARC IN WIRELESS TELEPHONY 155 



in Fig. 56, where the microphone is placed in shunt with 

 the inductance. Changes in the resistance of the micro- 

 phone will again produce changes in the intensity of the 

 oscillations about the arc. 



A further addition must be made to the apparatus in 

 order that the oscillations produced by the arc may be 

 radiated into space and to do this effectively it is necessary 

 to have a higher E.M.F. than that which would be given 

 by the device already described. For this purpose a step- 

 up transformer is introduced into the circuit in shunt with 

 the arc as shown in Fig. 56, where P is the primary of 

 the transformer and 5 is the secondary. One end of the 

 secondary is connected to the earth and the other to an 

 aerial wire. 1 



1 Partial list of articles published on the second method of wireless teleph- 

 ony which I have not otherwise mentioned: 

 Nussbaumer, Phys. ZS., 5, 796; 1904. 

 Ruhmer, Elektrot. ZS., 27, 1060; 1906. 

 Rozanski, Beib., 31, 845; 1907. 

 Brown, Lond. Elec., 58, 201; 1907. 

 Vreeland, Lond. Elec., 58, 685; 1907. 

 Blondel, Lond. Elec., 60, 216; 1907. 

 Fessenden, Lond. Elec., 59, 987; 1907. 

 Mosler, Elektrot. ZS., 28, 142; 1907. 

 Fleming, Lond. Elec., 59, 914; 1907. 

 Sahulka, Elektrot. ZS., 28, 1063; 1907. 

 Traubenburg, Elektrot. ZS., 28, 559; 1907. 

 Eisenstein, Elektrot. ZS., 28, 830; 1907. 

 Schapira and Loewe, Lond. Elec., Eng., Nov. 7; 1907. 

 Cartelli, Lond. Elec., 62, 609; 1909. 



