22 



Microscopical Essays. 



a lamp, by which means a piciure of microfcopic objects might 

 be exhibited in winter evenings. 



It appears * from the teftimony of M. ^Epinus, that M. Lie- 

 burkuhn had confiderably improved the folar microfcope, by 

 adapting it to view opake objeds. This contrivance was by fome 

 means loft. The knowledge, however, that fuch an effecl had 

 been produced, led ^Epinus to attend to the fubjeft himfelf, in 

 which he in fome meafure fucceeded, and would, no doubt, have 

 brought it to perfection, if he had increafed the fize of his illu- 

 minating mirror. Some further improvements were made on this 

 inftrument by M. Ziehr ; but the moft perfect inftrument of the 

 kind, is that of Mr. B. Martin, who publifhed an account of it in 

 the year 1774.+ The common folar microfcope does not mew 

 the furface of any object, whereas the opake folar microfcope not 

 only magnifies the objea, but exhibits on a fcreen an expanded 

 picture of it's furface, with all it's colours, in a moft beautiful . 

 manner. 



About the year 1774, I invented the improved lucernal 

 microfcope ; this inftrument does not in the leaft fatigue the eye ; 

 it fhews all opake objects in a moft beautiful manner ; and tranf- 

 parent objects may be examined by it in various ways, fo that no 

 part of an object is left unexplored ; and the outlines of all may 

 be taken with eafe, even by thofe who are moft unfkillcd in 

 drawing. 



M.L. 



* Prieftley's Hilr. of Optics, p. 743. 



t Martin's Defcription and life of an Opake Solar Microfcope. 



