QUEKETTS MICROSCOPE 



joint, G, by which the instrument can be inclined by turning the 

 screw-head, H [connected with an endless screw acting upon a worm- 

 wheel]. The arm, I, supporting the compound body, is supplied 

 with a rack and pinion, K, by which it can be moved backwards and 

 forwards, and a joint is placed below it, upon which the body can be 

 turned into a horizontal position ; another bar carrying ;i stage and 

 mirror can be attached by the screw. L N. so ;is to convert it hit > n 

 horizontal microscope . 

 The stage. O, is provided 

 with all the usual appa- 

 ratus for clamping ob- 

 jects, and a condenser 

 can be applied to its 

 under surface ; the stage 

 itself mav be removed, 



/ 



the arm, P, supporting 



it. turned round on the 

 pivot C, and another 

 stage of exquisite work- 

 manship placed in its 

 stead, the under surface 

 of which is shown at Q. 

 ' This stage is strictly 

 a micrometer one, hav- 

 ing rectangular move- 

 ments and a, fine ad- 

 justment, the move- 

 ments being accom- 

 plished by fine-threaded 

 screws, the milled heads 

 of which are graduated. 

 ' The mirror, E, is a 

 double one. and can lie 

 raised or depressed by 

 rack and pinion ; it is 

 also capable of removal, 

 and an apparatus for 

 holding large opaque. 

 ( >1 >jects, such as minerals, 

 can be substituted for it. 

 The accessory instru- 

 ments are very numer- 

 ous, and amongst the FlG<130 ._Martin' S large universal microscope as used 

 more remarkable may by Quekett (1780J. 



be mentioned a tube, M, 



containing a speculum, which can take the place of the tube. R. and so 

 form a reflecting microscope. The apparatus for holding animalcules 

 or other live objects, which is represented at 8, as well as a plate o|' 

 glass six inches in diameter, with four concave wells ground in it, 

 can be applied to the stage, so that each well may be brought in 

 succession under the magnifying power. The lenses belonging to 



