ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 
235 
On a base-plate which is clamped to the stage by the binding-screw M 
rises the stand S with the divided circle T, which is provided with a 
vernier reading to 5 minutes. The rod carrying the glass hemispheres of 
the Adams apparatus, between which the crystal plate is laid, can be 
rotated by the arc D for the adjustment of the plane of the optic axes. 
Fig. 30. 
The two hemispheres can be removed when desired, and replaced by the 
crystal-holder P or K. For axial measurements in liquids, the vessel 
G is used. This is attached to the angle-plate W, which is clamped 
to the base-plate by the screw M. 
The simple apparatus devised by C. Klein for the optical examination 
