APPENDIX. 



747 



stand, and the accessory apparatus can be adapted at any 

 time, without returning the instrument to the maker's 

 'lands. 



Fig. 359. Crouch's Microscope. Scale J. 



The latest improvement effected in this cheap instru- 

 ment is the adaptation of a concentric rotating stage, 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- 



