ioo Microscopical Essays. 



A B C D, Fig. 4, reprefents the body of the microfcope, con- 

 fiding of two brafs tubes. E F is the top of the inner moveable 

 tube ; the end e f of the fingle tooth and pinion microfcope, Fig. 

 g, fcrews into the top of this inner tube; at the end A B of the 

 external tube there is a lens, to receive the light of the fun from, 

 the mirror K L, and to collecl: and condenfe it on. the object ; the 

 end A B fcrews into the circular plate G H L 



K L, a long frame fixed to the moveable circular plate ; im 

 this frame there is a plane mirror to reflect the rays of the- 

 fun on the lens at AB'. 



An endlefs worm or fcrew, which is cut on the lower part o£ 

 the nut M, works in a fmall wheel which is fixed to the frame 

 K L, fo that by turning the nut, the frame K L is moved up or 

 down : the nut N moves the mirror to the right or left. 



0,P, two fcrews to faften. the fquare plate to the window- 

 fn utter. 



Fig. 5, the fingle microfcope; e f the end which fcrews on to 

 the upper part E of the internal tube of the body ; q the dove- 

 tailed flit for receiving the Aider, Fig, 8. 



g, the hole in which the megalafcope magnifier,. Fig. 6, is to 

 be fcrewed, when the Aider, Fig. 8, is removed. 



At h are the moveable plates, between which the Aiders are 

 placed ; under the lowermoft of thefe the lens reprefented at Fig. 



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