THE PINHOLE CAMERA 27 



a. Make a bow of the stick by means of the string, 

 having the string come over the ends of the stick. Sight 



along the tight string at a candle. Does the light come 

 to your eye in a straight line? 



b. Make a hole with your pencil point through the 

 center of one piece of cardboard, and hold it three or four 

 inches from the lighted candle. Hold the other piece 

 of cardboard near the first piece, on the side away from 

 the candle. What do you see? A darkened room is 

 best for this experiment. If you do not see anything 

 distinctly it may be because the hole is either too large 

 or too small. What you see is an image. Explain why 

 the image has the position in which you see it? If light 

 started from the top of the candle and passed through 

 the hole, in a straight line, would it strike the top or the 

 bottom of the second piece of cardboard? 



Experiment 16. How to Make and Use a Pin-hole 

 Camera. 



Materials: Chalk box, piece of ground glass to fit 

 as cover to chalk box, tinfoil, cardboard box, waxed or 

 greased paper to cover one end of cardboard box. 



a. Cut a hole in the center of the bottom of the 

 chalk box about one-quarter of an inch across. Cover 

 this hole with a piece of tinfoil and make a pin-hole in 

 it. Slide the ground glass into the chalk box as a cover, 

 with the ground side out. The camera is finished. 



b. Second method. Break one end out of a card- 

 board box, paste the cover on, and cover the open end 



