CfIRE Of THE EYES. 



Some trouble may at first be experienced by those unaccus- 

 tomed to the use of the microscope, but this will shortly be over- 

 come if due care is exercised. Always work with both eyes open 

 and divide the labor between the two. At first, it may be a little 

 troublesome to see the objects hi the microscope distinctly with 

 both eyes open, but by a little perseverance this can be overcome 

 and the objects outside will not interfere. 



A convenient form of an eye shade can be made by covering a 

 piece of card board, 10xl8c.m., with black cloth. Make a hole in 

 the card midway between the ends and 2c.m. from one side. Put 

 the shield over the ocular, letting it rest on the collar of the draw 

 tube. A rubber band fastened to the card will keep it in place. 

 (Fig. 7.) 



If. C.M. 



Fig. 7. Diagram of an eye shade. 



This shield will cut off the light from the eye not in use, and 

 be of material assistance. 



Do not use the microscope after the eyes become tired. The 

 fatigue which is troublesome at first will wear away in a short 

 time, and one will soon be able to work for hours with the instru- 

 ment without difficulty. 



