METHODS OF STUDYING VISION IN ANIMALS 



19 



which the experimenter may shift the lamp carriages without 

 approaching the hght box or experiment box. Fig. 2 presents 



FiGUHE 2 — Construction drawings for lamp carriages. Dimensions, unless otherwise 

 specified, are given in millimeters. Castings for the base of carriage may be 

 obtained through the writers. 



construction drawings of the lamp carriages. The rollers were 

 obtained from Francis Keil & Son, New York. They are known 

 as ball-bearing sheaves no. 17074. These rollers neatly fit a 



