The Prermce. 
World, and for the difcovery of many others hitherto unknown, and to make 
-ubgwith the great Conqueror,to be affecied that we have notyet overcome one 
World when there are fo many others tobe difcovered, every confiderable 
improvement of Telefcopes or Microfcopes producing new Worldsand 
Terra-Incognita’s to our view. | | | _ 
The Glaffes L ufed were of our Engli{h make,but though very good of the 
_ Rind, yet far fhort of what might be expetted, could we once find a way of 
making Glaffes Elliptical, or of fome more true fbape ; for though both 
- Microfcopes, andTelefcopes, as theynow are, will magnifie an Objett 
about a thoufand thoufand times bigger then it appears to the naked eye ; 
yet the Apertures of the Objeti-glaffes are fo very fmall,that very few Rays’ 
_ are admitted, and even of thofe few there are fo many falfe, that the Objeét 
appears dark and indiftinét : And indeed thee inconveniences are fuch,as 
feem infeparable from Spherical Glaffes, even when moft exatily.made;but 
theway we have hitherto made ufe of for that purpofe is (0 imperfett,that;there 
may be perhaps ten wrought before one be made tolerably good, and moft of 
thofe ten perhaps every one differing in goodne[? one from another, whichis 
an Argument,that the way hitherto ufed is,at leaft,very uncertain. So that 
thefe Glaffes have a double defett;the one,that very few of them are exatily 
true wrought 5 théeother, thateven of thofe that are. beft among them, none 
will admit a fufficient number of Rayes to magnifie the Objeét beyond a 
determinate bignef3.  Againft which Inconveniences the only Remedies I 
have hitherto met with are thee. = = Sats 
Firft, for AGcrofcepes ( where the Object we view is near and within our 
power)the beft way of making it appear bright in the Glafs,isto cafta great 
quantity of light on it by means of convex glafes,for thereby,thoughtheaper- 
ture be very {mall,yet there will throng in through itfuch multitudes,thatan 
Objec& will by this means indure to be magnifi'd.as much again’asit would 
be without it. The way for doing whichis this. Imake choice of fome 
Room that has only one window open tothe South, andataboutthreeor 
four foot diftance re this Window,on.a Table, Iplacemy Aécrofcope,and 
then fo place either a round Globe of Water, or a very deep clear plazo con- 
- -wex Glafs ( whofe convex fide is turn'd towards the Window ) that there 
is a great quan ars collected and thrown upon the Object: Orif — 
the Sun fhine, I place a {mall piece of oyly Paper very near the Object, be- 
tween that'and the light 5 then witha good large Burning-Glafs I {o collect 
and throwthe Rayes on the Paper,that there may bea very great quantity 
of light pafs through it to the Objett 5 yet I fo proportion that light, that it 
| may 
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