INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 



1065 



It also relates to a convex lens, either plano-sphcrical or piano- 

 cylindrical, in combination with a plano-concave lens, that can be 

 caused to traverse the surface of the plano-convex lens, and an illu- 

 mination-tube to direct a beam of liglit through tlie plano-concave 

 lens. 



It also relates to the convex lens and its support in the radius of 

 the circular track, in combination with an illuminating device. 



Fig. 12D. 



It also relates to a graduated circular track to support an ilhimi- 

 natiou-tubc and accessories, with tlie stage, to support the object-slide, 

 as will be mon; fully described hereiiiiifter. 



Ill the drawings, the base or stand lias jointed to it a curved arm A, 

 upon which the body of the iustruinout is mounted. It also carries 

 the stage S, upon which is placed the object-slide ('. I) represents a 

 circular track mounted upon a substago carriage B, connected to the 

 arm A. This circular track is mounted and carried on or within 

 guides in a plane parallel to the optical axis X X of the instrument 



