OOLOGY AND BOTANY, MICROSCOPY, ETC. 



309 



eliorfc tube, with outside screw. In this tube slides the socket to 

 which the stage is attached, and by the action of the screw (on the 

 principal tube being revolved) a fine adjustment is obtained. The 

 screw, though coarse, is of large diameter (l\ in.), so that the 

 motion is sufficiently slow. A coarse adjustment is made by sliding 

 the body-tube. On removing the stage the end of the Microscope 

 can be closed by a cap, for more conveniently carrying it in the 

 pocket. The total length is 7| in. 



Fig. 58. 



Fig. 59. 



Fig. 60. 



Klbnne and Miiller's Pocket Microscope. — This (fig. 59) is 

 similar in general design to the preceding, but is without any arrange- 

 ment for fine adjustment. The slide is passed through a transverse 

 opening in the drum which forms the end of the principal tube or 

 sheath, and is kept in position by the action of a spring, the two ends 

 of which move in slits as shown in the fig. There is an aperture in 

 the drum to admit light to the object. 



For use in the field the Microscope is carried in the case shown 

 in fig. 60, which contains knives, needles, glass tubes, and slides. 



Janney's Simple Solar (or Projection) Microscope.* — This 

 (fig. 61) is a somewhat primitive form of solar Microscope devised 

 by R. Janney, which however, on account of its cheapness and the 

 absence of a heliostat, may be found useful for school demonstrations 

 in countries where there is a fair amount of sunshine. It is claimed 



* Scientific American, 1. (1884) p. 276 (2 figs.). The fig. is from Zeitschr. f, 

 Instrumentenk., iv. (1884) p. 319, and slightly diifers from the original. 



