144 



ELEMENTARY CHEMICAL MICROSCOPY 



Bt 



FIG. 90. Zeiss Traversing Microscope or Comparator. 



heavy base. The stage S slides to the right and left in grooves; 

 it is provided with two sections S 1 , S 2 , of which S 1 may be moved 

 independently by means of the micrometer screw M 1 , thus per- 

 mitting a very exact adjustment of a point or line under the 

 cross-hairs of the microscope B. At the opposite end of the 

 stage a second micrometer screw M 2 displaces the entire stage. 

 The section s 2 carries a finely graduated scale whose rulings 

 are read by the reading microscope A of fixed focus. Each 



