ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



403 



srapliic objective in such a manner, that both could slide backwards 

 and forwards in movable sockets, on a bar 60 centimetres long, pro- 

 vided with a scale. The bottom of the bar bears the movable 



Fig. 68. 



object-stage, and under this is a microscope mirror. A glass plate 

 placed at "the side of the apparatus acts as the drawing surface. 



" This apparatus has been employed for years by Professor His, 

 but I have endeavoured to give it a more compendious form, and at 



