MICROMETRY MICROMETRIC MICROSCOPES 



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FIG. 91. Beck Micrometer Microscope. 



microscope is provided with a fixed ocular with cross-hairs mov- 

 able by micrometer screws attached to graduated drums D 1 , D 2 . 

 The pitch of the micrometer screws is identical in each instru- 

 ment. One complete revolution of a drum is an aliquot part 

 of one division on the scale of the stage S 2 . The object to be 

 studied is placed upon section S 1 of the stage and clamped in 

 place, the stage S having been first moved by hand by the knob K 

 to the most convenient place for beginning the measurements. 



