114 



THE MICROSCOPE. 



(A), which can be inclined at any angle, with a mirror 

 (c) on a ball-and-socket joint ; and a stage-plate with 

 universal movement. When about to be used as a 

 class microscope, the slide is placed in a shallow box, 

 into which it is locked by means of a key. The same 

 key locks this box firmly on the stage -plate. When 

 the object has been found, this latter can be secured 

 firmly on the stage in the same manner. After focus- 

 sing, the body is also locked in its place with the same 

 key, which is seen at D, the final adjustment being 

 made with the eye-piece. The body is then placed in 

 the horizontal position, and fastened with a screw. 

 The instrument can now be passed round a class-room 



FIG. 66. Murray and Heath's Class Microscope. 



without possibility of injury either to object or object- 

 glass. The illumination is obtained either by direct, 

 ing the instrument towards the window, or by means 

 of a small lamp (B), similar to that employed by Dr. 

 Beale, and which can be so adjusted as to be used 

 either for opaque or transparent objects. 



In Mr. Ladd's student instrument, such as that repre- 

 sented in fig. 67, he has taken great care to obtain 

 a perfect balance in any position, even when placed 

 in the horizontal axis ; no instrument can be better 

 adapted than this to the wants of the microscopist j 

 it is certainly one combining many of the advantages 

 of the more expensive forms. 



