1243 } ■ 
Scinds) and black on the other fide lor wbite ones of that 
nature. ' - 
Upon the fharp end. A, of this Brafs Inftrument all tlm 
8 GlalTes niay be fixed, you fee Fig. iV. n. 4, there be- 
ing a hole in the Ivory v/herein the GlaiTes are fet for that 
purpdfe, with a thin piece of Brals B in manncrof aSpri:ig, 
that holds if firmer : So when any Ob), ft is taken up in the? 
points of the Tongs k, or laid upon the other end H, it 
may be very eafily (asany one who fees the Inftrument will 
percdve) applyed to the true diftance of any of the Giaffes 
by the help ot the Joynts p p p p, as alfo the Screw C, and 
Wheel which ¥/ill bring the Objeft to the exaftnefs of 
the Cemer or true diftance, being regulated by a Spring 
The ufe of the firft mention'd Inftrument, Fig. L AAAA 
is thus : Take one of your Flat Pieces of Ivory E E 
or Regiders, (if you pleafe to call them fo.) and Aide it in 
betwixt the two thin Plats of Brafs E E in the bcdy^ot the 
Microfcppe,fo that the Objeft you intend to look upon be jaft 
in the middle, remarking that you put that Tide of the Plate 
E ExWhere the Ring is furthefl; from your eye : Then you are 
to fcrew into o o,Cthe bolIowScre w in the end of the boeiy of 
your Microfcope,Jthe gd, 4th, 5th, 6th or 7th Magnifying- 
Olafs 5 which being done, while y* are looking thro your 
Magnifying Glafs upon the Objed, you are to Screw in or 
out the long Screw D in the other end of the body of your 
Microfcope, till you bring your Objeft into the true Diftance^ 
which you will know by feeing the_Objeft Clearly , and 
Diftinftly ; But feeing that in the greater Magnifyers you 
can fee but a fmall part of the Objeft, vizi the Legs or 
Claws of a Flea 5 while you are looking upon, any part of 
the Objeft, if ye take hold of the end of the Plate E E, 
w^hereon the Objed: lyes, and move it gently, you may fee 
the whole Objeft fucceffively, or any part of the Ohjeft 
you pleafe t, and if that part of the Objeft you defign to 
look upon be outX)f the true Diftance, remerjiber your End 
Ffffffff2 Screw- 
