26 



THE AMERICAN MONTHLY 

 MICROSCOPICAL APPARATUS. 



[Jan. 



Attachable Mechanical Stage for Microscopes With 

 Plain Stages. — This Stag-e consists of a suitable base-plate 

 provided with thumb-screws fitting- into the clip-holes and 

 fastened from below. Upon the base-plate are two sliding- 



pieces mounted at rig-ht ang-les to one another and moved 

 in rig-ht lines by two milled heads. The perpendicular 

 movements are controlled by rack and pinion, and extend 

 an inch and a quarter. The horizontal movements extend 

 full two inches and are controlled by a micrometer screw. 

 These sliding- pieces pass along- suitable scales whereby 



