191 



Screw them into the nosepiece and unscrew, by 

 grasping the milled edge. 



Avoid any violent contact of the front lens with 

 the cover glass. Usually the latter suffers, but it 

 is as liable to injure the former. 



Above all, the owner should make it a rule that 

 no one except himself handles the microscope and 

 accessories. One person may be expert in the 

 manipulation of one instrument and still find it 

 difficult to work with another. The fine adjust- 

 ment particularly causes the greatest difficulty, as 

 in some instruments it corresponds with the move- 

 ment of the micrometer screw, while in others it is 

 contrary and thus the objective as well as the 

 object is endangered. 



