PSYCHOLOGICAL PROGRAM AND TECHNIQUE. 



163 



ulus lights may appear is about 25 cm. square. This area forms one 

 side of the lamp-house, H, which contains four 60-watt Mazda lamps. 

 The lamps were arranged upon a cluster plug; the inside of the house 

 was white, ground glass being used to diffuse the light. There were 28 

 stimulus units arranged in the door of the box which faces the subject. 

 A section of this part of the stimulus apparatus is shown diagrammati- 

 cally in figure 33 from within the box. TF is a three-ply wooden door. 

 On the outside of this, that is, near the subject, is a milk glass, G, and 

 over this a metal plate, painted flat 

 black and containing holes 2 mm. in 

 diameter, through which the light may 

 pass to the subject's eyes. Twenty- 

 eight small shutter devices, like that 

 shown at >S in figure 33, were arranged. 

 When opened by the cords C (which 

 extended to the operator's end of the 

 table, see fig. 30) they each exposed a 

 round hole in the door, 1 cm. in diam- 

 eter. In this way the light was al- 

 lowed to fall on the milk glass and a 

 certain portion of it went through the 

 opening in the plate to the subject's eye. 

 The shutters were all fitted with black 

 velvet, thus making them light-tight 

 when not operated. The four 60-watt 

 Mazda lamps were in parallel, as shown 

 at L in figure 34, and constantly in 

 series with the resistance R. Thus, 

 when contact was made at the mer- 

 cury switch, M (figs. 34 and 35) the 

 resistance R was swiftly short-circuited 

 and the lamp filaments came to full 

 brilliancy in a very brief interval.^ 



The circuit of the solenoid, S (figures 

 34 and 35) was completed by the sliding contact C (figures 30 and 34), 

 as explained in connection with the modifications made in the falling- 

 plate camera. From figure 35 it may be noted that when the solenoid 

 acted, the part designated as 1 was shifted to the left in the picture. 

 This caused the falling of the frame 2 resting on the top of 1 . This 

 frame carried the shield A, which interrupted the beam of hght until 

 that moment when the falling of this frame turned the photographic 



iln this report our interest is in comparative results. It may, however, be stated that 0.02 

 second for latency of apparatus should be deducted from the values as printed to reduce them to 

 an absolute basis. This factor was determined from photographic records taken specifically to 

 reveal the constants of the apparatus. 



•T 



Fig. 33. — Detail of the small shutters 

 and windows in the eye-reaction 

 stimulus apparatus. 



S, shutter controlled by cord, C, for open- 

 ing the 1 cm. holes, H, in the wooden 

 door W; the light thus came to the 

 milk glass, G, and a portion of it 

 passed through the 2 mm. opening in 

 the thin metal sheet, T, the exposed 

 surface of which was painted flat 

 black. 



