46 CANDLES TOO TALL. 



language, while, on the other hand, if, of these two kites of 

 exactly the same shape, one was only a little toy an inch 

 long, and the other were six feet long, we should not ordi- 

 narily say that they were similar. We should say that 

 they were very different. In a geometrical sense, however, 

 they would be similar, while the two that differed in form, 

 however slightly, though of the same size, would not be 

 similar. 



" Now," continued Lawrence, " if we cut a square hole 

 in a piece of paper, and let a light shine through it upon a 

 card, or sheet of paper, for a screen, held behind it, the 

 bright spot made on the screen will be similar to the open- 

 ing, provided the screen is always held square to the light. 

 The size of the bright spot would, however, be very differ- 

 ent at different distances, and the law of increase would be 

 as the squares of the distances that is, at twice the dis- 

 tance it would be four times as great; at three times the 

 distance, nine times as great; at five times the distance, 

 twenty-five times as great, and so on in all cases." 



" I mean to try it," said John. 



So saying, he rose from his seat, and, procuring a card, 

 cut a small square hole in the middle of it. He then put 

 one of the candles away in the closet, reserving the other 

 to form the source of light. The hole which he made in 

 the paper was about an inch square. 



He then put the reserved candle on the floor, and near it 

 placed a chair. On the chair he placed a big book, on one 

 end, in such a manner that he could slip the card between 

 the leaves at the other end,by which ingenious contrivance 

 the card was supported at about the height of the candle. 

 He placed the book so that the card should be at the dis- 

 tance of a foot from the light, and then held a sheet of 

 white paper at the distance of another foot. He found, as 

 Lawrence had said, that the bright spot was two inches in 



