MICROSCOPE ACCESSORIES 215 



Standardization of Ocular Micrometers. In 



standardizing micrometers the tube length should be 

 adjusted at 160 millimeters. Place the ocular microm- 

 eter slip in the ocular so that it rests upon the dia- 

 phragm of the latter. Place the stage micrometer 

 on the stage and focus so that the rulings are clear. 

 Move the stage micrometer slide and turn the ocular 



FIG. 70. Mechanical Stage. 

 (Bausch & Lomb.) 



until the stage and ocular scales correspond and the 

 end, line of the ocular scale coincides with a line of the 

 stage micrometer ruling. Count the number of spaces 

 of the stage scale covered by the entire number of 

 ocular micrometer lines. Divide the number of stage 

 micrometer lines covered by the total number of 

 ocular scale divisions. The quotient equals the value 

 in millimeters of each line of the ocular scale. 



