IMPERFECT VISUAL JUDGMENTS. 281 



(d.) Gum on to a sheet of white paper two strips of black 

 paper 5 mm. wide, and parallel to each other, leaving a white 

 interspace of 8 mm. between them. Look at the object, and, 

 especially if it be not sharply focussed, the smaller black 

 strips will appear broader than the white one. 



3. Imperfect Visual Judgments. 



(a.) Make three round black dots, A, B, 0, of the same 

 size, in the same line, and let A and C be equidistant 

 from B. Between A and B make several more dots of the 

 same size. A and B will then appear to be further apart 

 than B and C. 



(b.) Make on a white card two squares of equal size, 

 omitting the outlines. Across the one draw horizontal lines 

 at equal distances, and in the other make similar vertical 

 lines. Hold them at some distance. The one with hori- 

 zontal lines appears higher than it really is, while the one 

 with vertical lines appears broader i.e., both appear oblong. 



(c.) Look at the row of letters (S) and figures (8). To 

 some the upper halves of the letters and figures may appear 



SSSSSSSS 88888888 



Pig. 133. 



to be the same size as the lower halves, to others the lower 

 halves may appear larger. Hold the figure upside down, 

 and observe that there is a considerable difference between 

 the two, the lower half being considerably larger. 



(d.) Zb'llner's Lines. Make two lines parallel to each 

 other. Note that one can judge 

 very accurately as to their paral- 

 lelism. Draw short oblique lines 

 through them. The lines now 

 no longer appear to be parallel, 

 but seem to slope inwards or 

 outwards, according to the direc- 

 tion of the oblique lines. 



(e.) Look at Fig. 134, the long 

 oblique lines do not appear to be 

 parallel although they are so. Fig 13 4._ z <5i lner s Lines. 



