ROSSS MICROSCOPE. 



79 



of construction, in those parts especially which are most 

 liable to tremor, and to the due balancing of the weight 

 of the different parts upon the horizontal axis. The 

 "coarse" adjustment is made by the large milled-head 



Fig. 39. — Ross's No. la Large Microscope, with Binocular arrangement and 

 Object-glass. Scale J. 



B. Sub-stage of ditto, with new Achromatic Condenser. Scale J. 



situated just behind the summit of the uprights, which 

 turns a pinion working into a rack cut on the back of a 

 very strong flattened stem, that carries the transverse arm 

 at its summit. A second milled-head (which is here con- 



