396 



DR. J. C. MOTTRAM ON 



examined against a number of differently -toj:ied backgrounds, it 

 will be found that the blending distances are not the same for 

 different backgiounds. If, for instance, they be examined 

 against a white background, then in the case of nos. 1-7 no 

 pattern-blending occurs : the objects appear as black spots. If, 

 instead, the background be light grey, then the white blends 



Text-figure 9. 



A series of eye-spot patterns used in tlie experimeiit»clescribecl on p. 401, and set out 

 in Table I. The uppermost disc is white, the lowest black. The others contain 



gth of white, either concentrated in the 



! upperi 

 from above down |, |, f , |, |, f, and 

 centre, or in a ring round the periphery. 



with the background and leaves the central black area visible 

 after the white has ceased to be distinguishable from the back- 

 ground. This difficulty can be overcome by joining up a number of 

 two-component patterns, and then finding the blending distance; 

 this has been done in the following experiment. 



