Alfred Russel Wallace 



seen with but one eye, and therefore (when we are using both 

 eyes) being seen obscurely. But if we look at a flat object, 

 whether square or oblique to the line of vision, we see it of 

 exactly the same size with two eyes as with one because the 

 one eye can see no part of it that the other does not see also. 

 But in painting I believe that this difference of proportion, 

 where it does exist, is far too small to be given by any artist 

 and also too small to affect the picture if given. 



Again, I entirely deny that by any means the exact effect 

 of a landscape with objects at various distances from the eye 



can be given on a flat sur- 

 face; and moreover that 

 the monocular clear out- 

 lined view is quite as 

 true and good on the 

 whole as the binocular 



hazy outlined view, and 

 for this reason : we can- 

 not and do not see clearly 

 or look at two objects at 

 once, if at different dis- 

 tances from us. In a 

 real view our eyes are 

 directed successively at every object, which we then see 

 clearly and with distinct outlines, everything else — nearer 

 and farther — being indistinct; but being able to change 

 the focal angle of our two eyes and their angle of direc- 

 tion with great rapidity, we are enabled to glance rapidly 

 at each object in succession and thus obtain a general 

 and detailed view of the whole. A house, a tree, a spire, 

 the leaves of a shrub in the foreground, are each seen 

 (while we direct our eyes to them) with perfect definition 

 and sharpness of outline. Now a monocular photo gives 

 the clearness of outline and accuracy of definition, and thus 



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