THE EYE AND VISION. 117 



c. The eyelashes. 



1. Their position. 



2. Their length and shape. 



d. The sclerotic coat. What is its color ? 



e. The iris. 



1. What is its color ? 



2. What is its shape ? 



3. How does it change with a varying amount of 



light? 



4. What is an albino ? 



/. The pupil. 



1. What is it? 



2. What is its shape, size, and color? 



3. Compare the pupil with that of the cat, the dog, 



and other animals. 

 g. Sketch. 



C. The Formation of the Image. 



Apparatus. A double convex lens on a stand. A ground glass 

 screen. A candle in a stand. A wooden rod on which the lens, 

 screen, and candle may slide. 



I. THE IMAGE ON GLASS. 



Arrange the lens, the candle-flame, and the screen so 

 that the image of the flame may fall on the screen. 

 Compare the image of the flame with the flame. 



Notice : 



a. The size of the image. 



b. The position of the image. 



c. The distance of the image from the lens. 



