Microscopical Essays. 95 



it's place we muft infert the tube Y of the fingle microfcope that 

 we are now going to defcribe* 



Fig. 2, Plate V. reprefents a large tooth and pinion micro- 

 fcope ; at m, within the body of this microfcope, are two thin 

 plates, that are to be feparated, in order to let the ivory fliders 

 pafs between them ; they are prefled together by a fpiral fpring, 

 which bears up the under plate, and forces it againft the upper 

 one. 



The Aider, Fig. 3, that contains the magnifiers, fits into the 

 hole n ; any of the magnifiers may be placed before the objecl, 

 by moving the aforefaid Aider : when the magnifier is at the cen- 

 ter of the hole P,' a fmall fpring falls into one of the notches 

 which is on the fide of the Aider, Fig. 3. 



Under the plate m are placed two lenfes, for enlarging the field 

 of view on the fcreen : the fmaller of the two is fixed on a piece 

 of brafs, and is neareft the plate m ; this is to be taken out, when 

 the magnifiers, No. 4, 5, or 6, are ufed, or when the megalafcope 

 lens, Fig. 4, is ufed; but is to be replaced for No. 1, 2, 3. 



This microfcope is adjufted to the focus, by turning the milled 

 nut O. 



To use the Solar Microscope. 



Make a round hole in the window- Aiutter, a little larger than 

 the circle abc; pafs the mirror G NP through this hole, and 

 apply the fquare plate to the Aiutter ; then mark with a pencil 



