III. 



APPARATUS AND METHOD 



The ground plan of the problem box used in this experiment 

 is shown in Fig. i . The outside dimensions are 89" x 30". The 

 box is constructed of J4" soft pine, and is 6" deep. All runways 



*, 



GROUND PLAN OF APPARATUS 

 FIG. i 



and doors are 4" wide and 5" deep. The doors are made of very 

 thin metal and are so hung that they may be opened and closed 

 without appreciable noise. Especially is this true of doors Di 

 and D2 which are controlled by rods R and Ri. The entire sur- 

 face of the box is painted black. The food-box F is 16" x 20" 

 and is the only portion of the box not covered with glass. The 

 entire floor of the maze in front of the food compartment, with 

 the exception of the long runway from the center door D, to the 

 point O, is laid with No. 20 copper wire at J4" intervals. By 

 pressing a contact key a current from three dry cells is sent 

 through an induction coil which sends an induced current over 

 the entire system of wire on the floor of the maze. The strength 



