T. C. Mendenhall on the Sensorium. 157 
to watch this opening, and to close the circuit, by preae pe a 
e card. € 
Sponse are registered upon the band of paper by two dots, sep- 
arated by an interval approximating perhaps to one-fifth of an 
meh, Now by carefully measuring this interval and comparing 
r the time occupied by the somewhat complex operation of 
S perceiving the object and acting in response to that per- 
on. I introduce the exercise of judgment by giving 1m 
wa hand, and when a red ecard appears he is to close with his 
+ Dan 
figures, ; in 
. 1 a8 much as possible, as a circle and a triangle, operating 
: with them in the same manner as in case of two colors. To 
os eg the time intervening between the appea 
. . . b 
which if they exist, however, are destroyed by 
in z determinations concerning the exercise of 
