VISUAL PERCEPTION OF THE CHICK 



29 



Fig. 6 

 Reprinted irom Behavior Monographs, 1911. vol. 1, no. 2, p. 18. "Perspective of 

 light or 'brightness' apparatus. A, light box; C, D, compartments oi A; B, 

 partition between C and D;E,F, lids of A ; G, H, metal carriages carrying tungsten 

 lamps; // and KL, tracks for G and H; M, N, Starrett steel millimeter tapes; 

 0, P, apertures covered by Aubert diaphragms; R, Bausch and Lomb cooling 

 cell in light box; d, d', metal straps; y, aluminum plate sliding between d and 

 d'; T, tracks for y; V, stop for y; z, steel plate bolted to wooden end of light box; 

 h, screws attaching d to s; s, s, standard brass stimulus plates; p, brass frame 

 about aperture in y;r, hard rubber ring screwed to p." 



