Common Science 



FIG. 87. The great telescope of the Yerkes Observatory at Lake Geneva, 



Wisconsin. 



first lens makes an image many times as big as the 

 object; then you look at this image through a mag- 

 nifying glass, so that the object is made to look very 

 much larger than it really is. That is why you can 

 see blood corpuscles and germs and cells through a 

 microscope, when you cannot see them at all with your 

 naked eye. 



