Figure 1. Perspective of apparatus used in testing reactions to colors, forms, 

 and sizes. 



1. Hover box, O; G, inclined planes of wire mesh leading from exits E, of the 

 experiment box to the hover box. 



2. Illumination box. — H, left compartment; P, right compartment; L, stimulus 

 lamps; S ; metric scales. 



3. Experiment box. — A, entrance compartment; C, discrimination compartment; 

 B, gateway between A and C; D and D', electric passageways; Ni, N 2 , N 3 , glass 

 areas for illumination in the sliding frame F; M and M', cardboard shutters for 

 closing exits E; U and R, electric keys for separate control of lamp in O and read- 

 ing lamp (not represented in drawing) on outside of A, above R; K, stimulus key; 

 I, inductorium. 



The figure is symmetrical, hence the letters G, E, L, and S designate both the 

 parts which they respectively mark and the duplicates of these parts on the oppo- 

 site side of the figure. 



