42 HOW TO SEE WITH THE MICROSCOPE. 



joint, allowing the use of the instrument at any 

 of inclination; perpendicular and horizontal positions 

 are indicated by stops ; the coarse adjustment is accom- 

 plished by a sliding tube, the tube being but five and 

 one-half inches long, but capable of elongation to the 

 standard length. 



The fine adjustment is similar to that of the Centen- 

 nial a concealed lever moving the entire body ; this 

 adjustment is reliable and very delicate. The sub-stage, 

 plane and concave mirrors, swing in the same manner as 

 do those of the Centennial, having the object in its 

 centre, even when swung over the stage. 



The sub-stage carries the diaphragms, of which three 

 are furnished with the instrument. Any piece of sub- 

 stage apparatus, such as condensers, paraboloids, prisms, 

 in fact anything from the lists, can legitimately be 

 adapted to the sub-stage, or the same can be instantly 

 removed, with the mirror also, if desired, thus leaving 

 the stand free from any obstruction below the stage. 



The sub-stage slides up and down in strong dovetailed 

 grooves, and has centering adjustments by hand. The 

 weight of this little stand I judge to be about three or 

 four pounds; it can, on a pinch, be carried in one's 

 great-coat pocket. 



It is worthy of mention in connection with these two 

 stands of Mr. Zentmayer's, that the fine adjustment 

 has been removed from the front to the rear, or, as 

 Mr. Zentmayer says, " to the more stable part of the 

 instrument." The author, when his attention was first 

 called to these stands, regarded this change of the fine 



