20 RADIATION. 



not ; but they were a poor old pair, very loose in the joints, 

 and she was afraid they would hardly be of any use to 

 him. 



John said that the looseness of the joints would not be 

 of any consequence. So the old lady went out and pretty 

 soon returned with the spectacles. 



John's plan was to go into his own room to try his ex- 

 periment, as it would be necessary to darken the room, he 

 said, and he did not wish to interrupt his cousin's reading. 

 But Lawrence said he would like to see the experiment 

 himself. So John lighted a candle and closed the shutters, 

 following the directions given in his book. Then, placing 

 the candle on one corner of the mantel-piece, and going to 

 the farther corner of the room, with the spectacles and one 

 of Lawrence's cards in his hand, he attempted to form an 

 image on the paper in the manner we have already de- 

 scribed. 



