20 ROBERT M. YERKES 



Measurements Dimensions Dimensions Dimensions 



Of alleys Small Medium Large 



Width inside 10 cm. 30 cm. 60 cm. 



Depth 20 cm. 40 cm. 200 cm. 



Distance from center X 



to entrance doors 114.5 cm. 343.6 cm. 687.1 cm. 



Distance from release door 



to entrance doors 105.9 cm. 317.6 cm. 635.1 cm. 



Of strips for doors to slide in 



Thickness 1/4 in. 1/2 in. 7/8 in. 



Width 2 cm. 3 . 5 cm. 6 . 5 cm. 



Length 20 cm. 40 cm. 200 cm. 



Block for reward mechanism 



Width 6 cm. 10 cm. 15 cm. 



Length 10 cm. 30 cm. 60 cm. 



Depth 2 cm. 4 cm. 6 cm. 



Hole in block 



Diameter 4 + cm. 6 + cm. 7 + cm. 



Food cup 



Diameter at top 4 cm. 6 cm. 7 cm. 



Depth 2 cm. 4 cm. 6 cm. 



Cover for food cup 



Width 7 cm. 20 cm. 30 cm. 



Length 8(2+6) 14(4 + 10) 25(10 + 15) 



Space necessary for apparatus in use 



Width 10 ft. 20 ft. 30 ft. 



Length 12 ft. 20 ft. 36 ft. 



Certain suggestions concerning details of construction are of 

 practical importance. It is desirable, for the sake of uniformity, 

 to supply each box with a floor. This floor should be cut shorter 

 than the sides of the box so that the entrance and exit doors 

 may drop past it, thus discouraging attempts of subjects to 

 raise the doors. Or, if the floor is cut full length, a strip nailed 

 across the box just inside of the exit door will serve the same 

 purpose while giving support to the floor. 



Each box should have a wire netting cover on top. 



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