90 



THE AMERICAN MONTHLY 



[Mar., 



surface of the lens. The polished surface of the lens will 

 reflect light not only with a reduced intensity, but the 

 reflection will be of greatly diminished size, as it acts 

 like a convex mirror. If sunlight is allowed to fall 

 upon the convex surface, an exceedingly small and brill- 

 iant image of the sun will be seen upon it. If the con- 

 vex reflector is properly placed with reference to micros- 

 copical work, the direction of illumination will remain 

 quite constant during several hours of work. 



a — — ■ 



A/ 



d - 



The plan I have found best is to close the blinds of my 

 room and leave an opening in the window I am using 

 about twelve inches long and six inches wide. My 

 W'indow faces south, and the opening is in the middle of 

 the lower sash and about ten inches from the bottom of 

 the frame. Sunlight enters this opening quite early 

 enough for w^ork, and is available for several hours 

 during the day. 



All that is necessary to be done is to mount the con- 

 vex reflector on some form of stand which will allow it 



