Skiascopy and its practical application to the study of refraction . of light in the one portion ofthe pupil, while there is an erect movement in the two areas are distinct, and separated by an interme-diate zone of feeble illumination. As the light is made tomove back and forth in the proper direction, the two areasof light in the pupil are seen alternately to approach andseparate, narrowing or widening the intermediate zone. Asthe areas, under these circumstances, are generally band-like, or have comparatively straight margins, the effectis similar to that of the opening and clos
Skiascopy and its practical application to the study of refraction . of light in the one portion ofthe pupil, while there is an erect movement in the two areas are distinct, and separated by an interme-diate zone of feeble illumination. As the light is made tomove back and forth in the proper direction, the two areasof light in the pupil are seen alternately to approach andseparate, narrowing or widening the intermediate zone. Asthe areas, under these circumstances, are generally band-like, or have comparatively straight margins, the effectis similar to that of the opening and closing of a pair ofscissors. These appearances are represented in figure 19,which shows them with the mirror so turned as to separatethe two areas ; and figure 20, which represents them broughttogether by an opposite inclination of the mirror. Suppos-ing the upper part of the pupil to be more myopic, figure19 corresponds to the plane mirror facing down or the con-cave mirror facing up; and figure 20 shows the plane mir-ror facing up or the concave mirror facing
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectretinos, bookyear1896
