102 



Microscopical 



Essays. 



in it's proper fituation, and the object, flider between trie plates at 

 h ; adjuft the object to the focus of the magnifying lens by the 

 fcrew b, till the object appears diflinct and clear on the fcreen. 

 By moving the internal tube of the body, the object may be 

 placed at different diftances from the lens which is fixed at A B, 

 fo as to be fuffkiently illuminated, and yet not fcorched by the 

 lolar rays. 



Apparatus belonging to the common Solar Microscope. 

 Square plate and mirror. 



V 



The body, confiding of two tubes, one within the other. 

 " The fingle microfcope. 

 The megalafcope lens, Fig. 6. 

 The flider, Fig. 8, with fix lenfes. 

 The two fcrews O, P. 

 Six ivory Aiders and a talc box. 

 Some glafs tubes. 



A flider, or brafs cafe, containing a plane piece of glafs, and a 

 brafs flider with holes, into which are cemented fmall concave 

 glafles, defigned for confining fmall infects between the plane and 

 4 concave 



