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V. A IVay for Myopes to ufe Telefcopes mth» 
out Eye^GlaJfes, an ObjeEi-GlaJs alone becoming 
as ujeful to them, and fometimes more than a 
Combination of Glides. Com?nunicated to the 
Royal-Society, by J, T. Defagu- 
liers, LL. D. and F. R. S. 
Lemma i: 
W Hat is requir’d of a Telefcope is to give large," 
and diftind Vifion ; that is, to make the Ob* 
; ]eGc (as in GaliUds Telefcope) or its Image (as in the 
Telelcopes made up of Convex Lentes) appear under 
a great Angle, and to have all the Rays of thofe Pen- 
cils that enter the Eye, meet in a point upon the /ir- 
tina of the Eye, on their refpedive Axes. 
The firft Figure reprefents the Combination of two 
Convex Lentes for the Aftronomical or inverting Te* 
lefcope; where the above-mentioned Requifites are ob- 
tain’d. A B is the Objedl fuppos’d at a vaft diftance 
from the Oje<iiive Lens LL, fo that Rays coming 
from the extremity A of the ObjecSt, will fall upon the 
Lens L L, in the fame manner as if they were paral- 
lel to their Axis AX; and after palling the Glafs u- 
nitd at a, where they projed the Image of the Point 
A ; from whence diverging, they fall on the Eye- 
Glafs //, and having pafs’d through it, go on parallel 
to each other, and enter the Cornea, of a common Eye E, 
which unites thofe parallel Rays upon its Retina R R R 
at a, where the Image of a is projedcd : The fame 
may be faid of the Rays that come from B, and after 
their ' 
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