70 



HAROLD C. BINGHAM 



off and on at regular intervals and the on interval would equal the 

 off interv^al. 



The brass points were grouped so that one pair bore upon the 

 left, the other upon the right edge of the circumference of the disc. 

 By attaching to the right edge, for example, a single band of brass 

 equal to half the circumference of the disc, and to the left edge two 

 bands of brass each equal to one-fourth of the circumference, the 



A; or or 



Kevoluing Due 

 Non Conductor 



J)ouble Syy/fch 



Fig. 7 



Flicker apparatus. Schematic diagram showing how flicker stimuli were 

 produced. The lamps were mounted on the movable carriages in the same source 

 compartments described in Chapter III. By means of the double switch shown 

 in the wiring scheme it was possible to alternate between the two lamps the slow 

 and rapid flashes. The revolving disk is illustrated in this figure as much too 

 large when compared with the illustration of the motor. The worm gear reducer, 

 described in the text, is not shown in the illustration. 



lamp connected through the right pair of points would have on 

 and off intervals twice as long as the intervals of the other lamp. 

 But, for any period of time, the total of the 07i or off time of the 

 one lamp would equal the same of the other lamp. Similarly, the 

 on and off flashes of the one lamp could be divided so that the 

 intervals were one-third or one-fourth of the intervals of the other 

 lamp. 



