92 PRACTICAL TREATISE ON THE MICROSCOPE. 



plan as the last described, but is much smaller, and only 

 capable of being used in the upright position; it is repre- 

 sented by fig. 2. The stand is supported on three feet, 

 AAA, having two flat upright cheeks, B B, connected with 

 them, to the top of these the stage-plate, D, is fixed. The 

 tube, G, is screwed into the upper surface of the stage-plate. 

 Within it, as in the larger instruments, a smaller one slides, 

 having the arm, H, supporting the tube, I, connected with it. 

 Through the tube, I, slides very smoothly up and down the 

 compound body, L, carrying the eye-pieces and object- 

 glasses ; this forms the coarse adjustment, whereas the fine 

 adjustment is made by turning the screw with milled head, 

 E, which either raises or depresses the arm, H, and the entire 

 compound body, L I, with it, in the same manner as was 

 described in the preceding instrument. A diaphragm, K, is 

 fitted into the bottom of the stage-plate. The mirror, C, is 

 supported on trunnions working in the front part of the 

 cheeks, B B ; but having only a circular movement, hence it 

 is required that the fight to illuminate objects should be 

 always in front of it. A stand of this description is ex- 

 ceedingly useful for keeping on the table where dissections 

 are going on, as small portions of the different tissues can 

 readily be placed under a quarter-of-an-inch object-glass, and 

 be examined as they are removed, the shortness of the stand 

 allowing of its being used without much trouble ; and almost 

 aU objects, for temporary purposes, being mounted in fluid 

 between glasses, they are apt to sfip down when placed on 

 the stage of an inclined instrument; and as aU the large 

 microscopes are too high to be used on a table at which dis- 

 sections are carried on, without either being inclined or the 

 dissector being obhged to get up from his seat every time an 

 object placed between glasses, with or without fluid, is re- 

 quired to be examined in the horizontal position, this little 

 instrument is extremely useful for these purposes, and 

 two such, one provided with a power of forty, the other 

 with that of two hundred, should be always at hand; 

 they are most efficient working tools, the cost of each 

 without glasses not exceeding £3. The sliding up and 



