ZOOLOGY AND BOTANY. MICROSCOPY, ETC. 
381 
arm provided with two fine-adjustments ; one at with a spring 
and clamping-screw serves for the azimuthal adjustment of the tele- 
scope ; the other serves to turn A, with respect to A^^, and plays 
the part of the micrometer-screw in the screw Microscope. The Micro- 
scope M2, which is used for reading the vertical scale, is connected in 
the same way with a micrometer screw S2, which, after the telescope is 
adjusted to the right elevation, serves to measure the interval between 
the cross-wire and the image of the nearest division. 
Fig. 33 . 
the telescope supports are attached to the arm A^ which is adjusted by 
the fine-adjustment, so that in using the micrometer-screw it is only 
necessary to turn the Microscope-carrier through the small angle to bo 
measured, while the telescope remains unmoved. The construction is 
