no HOUSE, GARDEN, AND FIELD 



but the same as that of the illuminated object. Suppose 

 next that the hole is appreciably enlarged, what will be 

 the effect upon the image ? The rays from any luminous 

 point, such as the candle-tip, will now enter the box not 

 as a mere line, but as a cone, and at the screen the cone 

 will be just twice as broad as at the hole. The images 

 of other points will spread out in like manner, and over- 

 lap ; the general shape of the whole candle-image will 

 remain the same as before, but it will be blurred. If we 

 continue to enlarge the hole, the image will become very 

 indistinct, and at length so much light will be reflected 

 from every part of the inside of the box that there will 

 be no visible image at all. 



This simple experiment of the pin-hole camera explains 

 the circular spots on the pavement. The chinks between 

 the leaves replace the pin-hole ; the sun replaces the 

 candle ; and the pavement is the screen. We get images, 

 not of the chinks but of the sun, and as the chinks are 

 often too large for good definition, the images are blurred. 



Proof that this is the true explanation can be got by 

 observing what takes place during a partial eclipse of the 

 sun. When the bright disc becomes crescentic, the patches 

 on the pavement become crescentic too. I have before 

 me a photograph of a pavement overshadowed by trees, 

 which was taken at Bombay during the partial eclipse of 

 1898, and all the bright patches are crescentic. 



Photographers can get very fair pictures of the view 

 from any window without using a lens. They employ a 

 pin-hole to form the image, and you could hardly distinguish 

 such a picture from an ordinary camera photograph, 

 though you would not consider it highly successful. 



XXI. THE SONG OF THE SKYLARK. 



When a lark leaves the ground, and rises with jerky 

 flight into the sky, singing lustily all the while, we are 

 astonished to hear him pour out his music while he is 



