ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 



515 



the subject of an elaborate series of patents registered in England by 

 M. Jaubert in 18G6, to wbicli we propose to refer hereafter. 



Mr. J. Mackenzie also describes and figures * a swinging sub- 

 stage made upon the same principle as the preceding. To the under 

 part of the fixed stage-plate an angular plate is attached, having a 



Fig. 117. 



swivel joint on which a stem with rack swings. A pinion works on 

 the rack and carries an arm with either a single or compound lens 

 which should be so adjusted as to be central with the optical axis of 

 the Microscope. At the end of the stem is a small concave mirror. 

 The lens can be raised or lowered by the jjiuion or swung to any 

 angle below or above the stage. The angle-plate should be made and 

 fixed so that the centre of the movable joint or swivel coincides with 

 the top of an ordinary object-slide when it lies on the stage. 



* Journ. Quck. Mirr. Club, vi. (1880) p. 170. pi. xii. 



