56 HOW TO SEE WITH THE MICROSCOPE. 



LARGE STUDENT'S MICROSCOPE. 



Heavy japanned cast-iron foot, with highly finished 

 brass pillars, carrying- the axis for inclination of the 

 body ; brass arm ; coarse adjustment by rack and pinion ; 

 fine adjustment by a new and patented motion. The 

 special advantages claimed for this new adjustment are : 

 (1) exceedingly easy and smooth movement ot the fine 

 screw both ways; (2) perfect freedom from all lost 

 motion; (3) perfect freedom from any side motion of 

 the image ; and (4) extraordinary durability. 



The microscope is provided with a movable slide 

 holder, serving as a substitute for a mechanical stage. 

 This slide holder consists of a German-silver plate of 

 very light weight, moving on a strong glass plate which 

 forms the immovable stage; only four small points of 

 the German-silver plate touch the top of this glass 

 stage, while two prolongations of the former, bent 

 downward and backward, and acting as springs, press 

 against the underside of the glass plate with just suffi- 

 cient force to keep the slide holder in position, and to 

 prevent it from slipping off when the instrument is 

 inclined. Two small knobs facilitate the handling of 

 this slide holder, and it is claimed that this arrange- 

 ment exceeds in smoothness and evenness of motion the 

 movable glass stages commonly used, while the mova- 

 ble part has less weight, and allows the glass plate to be 

 of sufficient strength to guard against easy breaking. 



The instrument has also plane and concave mirrors ; 

 sub-stage of the extra size required to receive standard 



