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C
vii Vlll
curvature (centrum, c) towards (i, iii) or away from (ii, iv) the object, or the centre of
curvature on the side of the object towards (vi, viif) or away from (v, vii) the eye.
A confusion between the appearance of size and of nearness, which led Bacon inx
correctly to draw a diminished image in i and a magnified image in iii, is corrected
in a later section of the Opus Majus* where Bacon points out that *the size of the
(visual) angle is the pcevailing factor in these appearances*; that is, the angle sub>
tended by the object oc^he image at the eye. He recommended a convex lens fbrav
ing a hemisphere (vi) or kss than a hemisphere (v) to aid weak sight.
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