230 



ANNAL.S NFJW YORK: AVADJJMY OF HCJEXCES 



of , using his valve. A group of high-frequency oscilJations impressed on 

 t}ie grid causes corresponding higli-frequency variations in the continuous 

 current in the wing current, but owing to the fixing of the grid potential 

 at the lower bend of the curve by adjustment of the potentiometer in the 

 g;^id.pircuit^ithe amplitude of the positive 23art of the high-frequency cur- 

 rent in the wing circuit exceeds the amplitude of the negative part. As 

 tlie positi\e half-waves are greater than the negative half-waves, more 

 electricity flows in one direction than the other, and the condenser C\, 

 through which the high-frequency current in the wing circuit flows, be- 

 comes charged, the side connected to the battery B^ having the positive 

 charge. This charge accumulates in C\ in a relatively short time, ap- 

 proximately that of the duration of a wave train. C\ then discharges 



t^ji^ pC^^t/^f 



Wtnq cm-renf 





lek/^eme c^rr-i^ent 



Fig. 12 



through tlic telephone T, the rate of this discharge being determined by 

 the constants of the telephones and the condenser. It is probable that 

 this discharge is aperiodic or nearly so. In any case the main part of the 

 discharge through the telephones is in the same direction as the current 

 due to the battery B., and constitutes an increase in the current in the 

 telephones. As this action is repeated for each group of oscillations, a 

 series of Avave trains causes what might be regarded (in its action on the 

 telephones) as an alternating current in the telephones superposed on 

 the continuous current and having a fundamental frequency equal to the 

 number of wave trains per second. The action is shown diagram- 

 matically in Fig. 8. 



\ If the potential of the grid is adjusted to the upper bend in the curve 

 of Fig. 1, as at point A, the fundamental action will be the same, but the 



