1893.] 



MICROSCOPICAL JOURNAL. 



101 



position ; and, second, that the aperture is too small to admit of 

 the employment of the finger in moving the slide to assist in rapid 

 focusing." He adds : "■ But these are defects which might cer- 

 tainly be oyercome." 



The improyed "super-stage" now described is believed to 

 obviate these objections, and is not only '' an efficient substitute " 

 for a mechanical stage, but a most desirable substitute for usual 

 work with the microscope ; permitting, as it does, absolute free- 

 dom of movements about a Held for full two inches horizontally 

 and one inch vertically, thus allowing ample room for even serial 

 sections ; and possessing, as it does, exquisitely smooth sliding 

 movements, over the stage proper of the microscope, of almost 

 absolute precision. My carriage and stage, made for me a year 

 ago by Zentmayer of Philadelphia, after my own specifications, 

 is of such excellent workmanship as to give perfectly level and 

 precise movements under a power of 2,250 diameters (Zeiss 1-12 

 homo, immers. x iS compens. ocular). 



The drawing shows in Fig. i a plan of the sliding-carriage, 

 and in Fig. 2 a cross-section on a vertical central line. The 

 stage should have two flat rails, one on each side of its aperture, 

 slightly raised above the surrounding surface, on which the 

 carriage slides ; and the stage may be square or round in shape, 

 as preferred. The outlines of the carriage are shown by the full 

 lines of the figures. Affixed to the bottom of the carriage are 

 glass rails A and B, of which the outlines and positions are 

 indicated by dotted lines. These glass rails of the carriage slide 

 on and over the metal rails of the stage. The circles aa and b 

 show respectively knobs for hold-fasts and a centring-stop for 

 object-slide C, indicated by the broken lines of the figures. 

 A spring clip, c, is provided, which can be swung against the 

 upper side of the slide, as indicated by dotted lines in Fig. i, to 

 hold it securely in place when the stage is perpendicular or 

 while it is rotated, or swung aside out of the way as shown by 

 full lines. The slide rests with sufficient security against the 

 ledge of the carriage when the stage is level or inclined, free 

 from being clipped in a rigid position, justly criticised as 



