W. LeConte Stevens—Physiological Optics. B51 
values of the optic angle, taken as abscissas; RR’ curve 
of far-points, PP’ that of near-points, and hat of distances 
Ing to @ = 25°, showing that, for values of the optic angle 
greater than this, distinct vision of an object as near as the 
optic vertex is impossible. This limiting value of the optic 
angle becomes still smaller with increasing age. The range of 
available accommodation in the present case is seen to be great- 
est when a = 3°30’. This is about the angle enclosed. by the 
visual lines when a single point is seen at the distance of 1”. 
4. 
Near points 
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