C ^4» ) 
requifite apertures, and inferted them at the ends of 
Tubes of (evearl lengths ; and find, thattho' thefe na- 
tural lenres may ferve as Eye Glafles, yet when ufed as 
Objed ones either to Telifcopes or double Mifcrofcopes : 
their Effeds will not compenfate the trouble there is in 
ufing them. 
I ihall now proceed to give you the D^fcription of my 
Natural Refleding Microicope. 
A Fig,-^, Reprefents a fmall flat Ring of Brafs, whoft 
rior Circle muft not much exceed 4 Tenths of an Inch 
Diameter, and about one thirtieth of an Inch thick • 
this we may call the Frame or Cell of the Glafs, it muil 
be prepared for ufe after the following manner. Take 
a fmall Globule of Quickfilver and diflblve it in a few 
drops of Aquafortis^ to which you may add ten parts 
of common Water, dip the end of a ftick in this Liquor 
and rub the inward Circle of the Ring with it, to it 
will have acquired a Mercurial TmcSure, and being 
wiped dry, be fit for ufe. Then let it be laid on the 
Table, and pour a drop of Quickfilver within it , 
which preft gently with the ball of the Finger, and ic 
will adhear to the Ring , then cleanfe it with a Hares 
foot, and you will h^vG z Convex Speculum* Take up 
the Ring and Speculum cmylug it Horizontal, and lay 
it on the brims of the hollow Cilinder B, (o will the 
Mercury become a Concave Reflecting Speculum, 'wh.ch 
from the fmallnefs of the Sphaere of which it feems to 
be a Sedlion, may be ufed as a Microfcope. The Cilin- 
drickVefTel B. has a Screw hole at bottom, by which 
it is fcrewed to the top of the Pedeftal CD, C E FG/n 
the Supporter of the Objedt Plate, which as you fee 
may be railed higher, or let low^er as there is occafion 
by the fcrewon the Pedeftal: The Objed Plate rauft 
be of Glafs cemented to the Ring G. 
This 
