APPENDIX. 747 



stand, and the accessory apparatus can be adapted at any 

 time, without returning the instrument to the maker's 

 hands. 



Fig. 359. Crone*'! 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 (fig. 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- 



