ii4 



Microscopical Essays. 



Description of Lyonet's Anatomical Microscope, 

 Fig. 3, Plate VI. 



Fig. 3 reprefents the inftrument with which M. Lyonet made 

 his microfcopical and wonderful diffe6lion of the chenille de iaule, 

 of which afpecimen is given in Plate XII. Fig. 1, &c. of this work. 

 This little inftrument needs no further recommendation ; aided 

 by it, other obfervers may be enabled to diflect other infe&s with 

 the fame accuracy as M. Lyonet, and thus advance the know- 

 ledge of comparative anatomy, by which alone the characleriftic, 

 nature, and rank of animals, can be truly afcertained. 



A B is the anatomical table, which is fupported by the pillar 

 N O ; this is fcrewed on the foot C D. The table A B is pre- 

 vented from turning round, by means of two fteady pins ; in this 

 table or board there is a hole G, which is exactly over the center 

 of the mirror EF, that is to reflea the light on the object; the 

 hole G is defigned to receive a flat or concave glafs, on which the 

 objecls are to be placed that you defign to examine. 



R X Z is an arm formed of feveral balls and fockets, by which 

 means it may be moved in every poflible fituation ; it is fixed to 

 the board by means of the fcrew H ; the laft arm I Z has a female 

 fcrew, into which a magnifier may be fcrewed as at Z. By 

 means of the fcrew H, a fmall motion may be occafionally given 

 to the atm I Z, for adjufting the lens with accuracy to it's focal 

 diftance from the object. 



Another chain of balls is fometimes ufed, carrying a lens to 

 throw light upon the object 5 the mirror is alfo fo mounted, as to 



be 



