Microscopical Essays. gj 



The main pillar a b is fixed in the box b e, and by means of 

 the brafs foot d is fcrewed to the mahogany pedeftal x Y, in which 

 is a drawer containing all the apparatus. 



a milled-headed fcrew, to tighten the bar F when the ad- 

 juring fcrew c g is ufed. 



p q is the ftage, or plate, which carries the objects ; it has a 

 hole at the center n. 



G a concave mirror, that may be turned in any dire&ion, to 

 reflect the light of the candle, or the fey, upon the object 



To use this Microscope. 



Screw the magnifier you intend to ufe to the end c of the 

 body, place the flider-holder P in the hole n, and the Aider with 

 the object between the plates of the flider-holder ; fet the upper 

 edge of the bar D E to coincide with the divifions which corref- 

 pond to the magnifier you have in ufe, and pinch the milled nut ; 

 now reflect a proper quantity of light upon the object, by means 

 of the concave mirror G, and regulate the body exactly to the 

 eye and the focus of the glafles, by the adjufling fcrew c g. 



To view opake objects, take away the flider-holder P, and 

 place the object on a flat glafs under the center of the body, or 

 on one end of the jointed nippers o. Then fcrew the filver con- 

 cave fpeculum to the end of the cylinder L, and Aide this cylin- 

 der on the lower part of the body, fo that the upper edge thereof 

 jmay coincide with the line which has the fame nlark with the 



L magnifier 



