65 Microscopical Essays. 



demand I have had for them, has fully repaid my pains and ex« 

 pences, in bringing it to it's prefent ftate of perfection. 



As the far greater part of the objects which furround us are 

 opake, and very few are fufficiently tranfparent to be examined 

 by the common microfcopes, an inftrument that could be readily 

 applied to the examination of opake objects, has always been a 

 defideratum. Even in the examination of tranfparent objects, 

 many of the fine and more curious portions are loft, and drowned 

 as it were in the light which mult be tranfmitted through them ; 

 while different parts of the fame object appear only as dark lines 

 or fpots, becaufe they are fo opake, as not to permit any light to 

 pafs through them. Thefe difficulties, as well as many more, 

 are obviated in the lucernal microfcope ; by which, opake ob- 

 jects, of various fizes, may be feen with eafe and diftinctnefs ; 

 the beautiful colours with which moft of them are adorned, are 

 rendered more brilliant, without changing in the Ieaft the real 

 tint of the colour. The concave and convex parts of an object: 

 retain alfo their proper form. 



The facility with which all opake objects are applied to this 

 inftrument, is another confiderable advantage, and almoft pecu- 

 liar to itfelf ; as the texture and configuration of the more tender 

 parts are often hurt by previous preparation, every object may 

 be examined by this inftrument, firft, as opake, and afterwards, 

 if the texture will admit of it, as tranfparent. 



The lucernal microfcope does not in the leaft fatigue the eye ; 

 the object; appears like nature itfelf, giving eafe to the fight, and 



pleafure 



