APPENDIX. 



74< 



stand, and the accessory apparatus can be adapted at any 

 time, without returning the instrument to the maker's 

 hands. 



Fig. 359. — Crouch's Microscope. Scale \. 



The latest improvement effected in this cheap instru- 

 ment is the adaptation of a concentric rotating stago, a 

 most convenient and useful addition. This stage (tig. 360) 

 is an adaptation of Nachet's principle, and consists of: a, 

 a lower plate or stage attached to stand in the ordinary 

 manner, with fitting beneath (f) to receive the accessory 

 illuminating apparatus. b is an upper plate rotating con- 



