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notice that three reflected images are to be seen one large, 

 clear, distinct, erect image from the anterior surface of the 

 cornea, one small distinct inverted image from the posterior 

 surface of the lens, and one much less distinct erect image, 

 larger than the first and apparently lying almost behind it 

 and seen best from the side away from the light, from the 

 anterior surface of the lens. From the size of these images 

 draw conclusions as to the relative curvatures of the different 

 surfaces. 



Why is no image formed from the posterior surface of the 

 cornea ? 



From the results of these observations, make a diagram of 

 the Physiological Lens of the Eye. 



III. Can Near and Far Objects be seen at the same Time ? 



METHODS. A. Close one eye and fix the other on the far 

 corner of the room, and then hold up a pencil at about a foot 

 from the eye and see if at the same time both objects can be 

 distinctly seen. Another student should note any change in 

 the pupil when the eye is directed to the pencil. 



B. Schemer's Experiment. Make two holes in a horizontal 

 line in a sheet of paper so near that they both fall within 

 the diameter of the pupil. Now stand at about two or three 

 yards from a wall on which a small vertical line is drawn and 

 look at it through the holes. While keeping the eye fixed on 

 the line, bring a needle vertically in front of the holes at about 

 eight inches from the eye,, and note the appearance of the 

 needle when the distant line is looked at, and of the line when 

 the needle is looked at. 



Make a diagram of the experiment and formulate the con- 

 clusions to be drawn. 



IV. Is the Power of Focussing Limited or Unlimited ? 



METHOD. Bring a pencil point held vertically nearer and 

 nearer to the eye ; a point is reached within which it cannot 

 be distinctly seen the near point. Measure the distance of 

 this from the eye and record it. 



