104 THE MICROSCOPE. 



unaccustomed to use the microscope. In order to avoid 

 this risk, Messrs. Murray and Heath have constructed au 

 instrument intended to combine an ordinary with a de- 

 monstrating or class microscope. It consists of the usuai 

 microscope body (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 a* 

 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 focussing, the 



Fig. 58. Murray and Heath's Class Microscope. 



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 posi- 

 tion, and fastened with a screw. The instrument can now 

 be passed round a class-room without possibility of injury 

 either to object or object-glass. The illumination is ob- 

 tained either by directing 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. 



This instrument appears to be particularly well adapted 

 to the purposes for which it is intended, and, at the same 

 time, if without the contrivance for locking, to be a useful 

 portable form for general, professional, or sea-side pur- 

 poses. 



