70 The Microscope. 



into the wall. There is a large elm-tree beyond the 

 buildings, and I can see its branches over the roof, 

 standing out against the sky. I have the microscope 

 on the table before me, inclined as much as if it were 

 a telescope, and facing the window, and I arn looking 

 through it at the scrap of a dragon-fly's eye, with a 

 magnifying power of 250 diameters. 



First, I screw the microscope very close to it, that 

 I may see the beautiful hexagons clearly. Next, I 

 gradually move the microscope a little farther from 

 the object ; the hexagons now become indistinct, and, 

 as it were, melt into each other, but in the centre of 

 each appears every particular of the view I have just 

 described ! There are the sashes of the window, the 

 arm-chair, the slated roof, the archway, the carved 

 stone, and the distant tree ! 



A sight of this singular object suggests various 

 questions to the mind of the thoughtful observer. 

 How did the insect see through all these eyes ? Why 

 did it possess such an extraordinary number ? and, To 

 what part of our eyes did these numerous little lenses 

 correspond ? A few words then may be acceptable 

 on the structure of insects' eyes. 



The hexagonal lenses correspond to the combined 

 action of the crystalline lens and cornea of our own 

 eyes. Behind each of them is a little " dark room," 

 not spherical, like ours, but shaped like a very long 

 hollow cone or pyramid. These thousands of pyramids 

 are all completely isolated, from each other by layers 

 of dark pigment, and at the inner extremity of each 

 there is a delicate filament, which is no other than a 



