Microscopical -Essays. 

 The Aider with the magnifiers. 



The megalafcope magnifier. 



The two fcrews Q and R. 



Some ivory Aiders. 



Some Aiders with opake objects, 



A brafs frame, with a bottom of foft deal to ftick any object on. 



A brafs cylinder K, Plate IX. for confining opake objects. 



Description of the common Solar Microscope, 

 Fig. 4, Plate VI. 



The foregoing defcription will, in a great part, anfwer for this 

 microfcope ; and I once intended to have made only fome general 

 references to the former, in order to avoid that prolixity which 

 muft ever attend the detail of defcription : but when I confidered, 

 that one of thefe inftruments might be purchafed by thofe who 

 would probably never fee the other; and that a fmall difference 

 in conftru&ion would embarrafs the young practitioner, it ap- 

 peared to me more eligible to give a defcription of the common 

 folar at full length, than to curtail it through an affectation of 

 brevity. 



This inftrument is reprefented in Plate VI. at the Figures 4, 

 & 6 > 7> 8. 



N. 2 A B 



99 



