Microscopical Essays. gg 



The life of each article of the apparatus, and the method of 

 applying it to life, will be defcribed in the latter end of this 

 chapter. 



Of the improved Compound Microscope, represented 

 at Fig. 2, Plate IV. 



The advantages of this over the preceding compound micro- 

 fcope, oonfifts, firft, in the motion which may be given to the 

 body, the flage, and the mirrors, by means of the joint c d, 

 which has both a vertical and horizontal motion ; fo that the 

 micro fcope may be placed either in an horizontal or inclined 

 fituation, and thus be adapted to the eafe of the obferver, and 

 be ufed when he is fitting down. If the mirror OOR is 

 taken off, the light will be conveyed in a direct, line to 

 the object, without any reflection. Secondly, that the body may 

 be moved over any part of the ftage, and thus over the object. 

 The arm which carries the body, moves to the right or left on a 

 central pin, and may alfo be moved backwards or forwards by the 

 milled nut b. Thirdly, the concave and flat mirrors are much 

 larger than thofe of Fig. 1. In every other refpecf, the micro- 

 fcope is fimilar to the foregoing, and may be managed by the 

 defcription thereof ; for which purpofe, fimilar letters are affixed 

 to the fame parts. 



A Description of Culpeper's, or the three-pillared 

 Microscope, Fig. 3, Plate IV. 



This inftrumem is recommended by it's fimplicity and cheap- 

 nefs ; it is e a lily managed, and gives a pleating view of an ob- 



M . " jeel 



