( 400S ) 
G D an Iron wire y holding a ring of brafs:^ in wBich the 
Ipeculura CD is fixed* 
F^a fmall Eye-g!afs flat above^ and convex belowj of the 
twelfth part of mc\\ radius^ ii notlelsi forafmuch as the 
metal colledls the Sun's rays at 6f inches diftance, and the 
Eye-glafsatlefs than? of an inch diftance from its vertex % 
Befides that the Author (as he informs us) knew their di- 
menfions by the tools to which they were ground, and par* 
ticulaily meafuringthe diameter of the hemi spherical Con- 
cave , in which the Eye.glafs was wrought^ found it the /ixtb 
part of an inch. 
GG G, thefore part of the Tube faftn'd to a brafsi-ring. 
HI, to keep it immoveable. 
P^i^L, the hind-part of the Tube, faftn'd to another 
brafs-ringPQ,* 
O, an Iron hook faftn'd to the Ring and furniflit 
with a fcrew thereby to advance or draw back the hind« 
part of the Tube, and ib by that means to pul ^Q /pecul^ . 
in their due diftance. 
M §1^1 a crooked Iron fuftaining the Tubej^ and faft- 
ned by the nail R to tJae Ball and Socket S , whereby the 
Tube may be turned every way.: 
The Center of the k^v fpeculMm. CD, muft be placed in 
the fame point of the Tube's Axe, where falls the perpen- 
dfcular to this Axe^ drawn to the fame from the center 
of the little Eye^glafs : which ppiot is here marked ; 
And to give the Reader fome fatisf^ftion to underftand, in 
what degree it reprefents things difticcSt, and free from co- 
lours, and to know the aperture by which it admits lights 
he may compare the diftances of the focus E from the ver- ^ 
te:Xs of the little Eye-glafs and the Concave fpeculumy that is, 
EF, I of an inch, and Elf V^^l inches; and the ratio 
be found as i to 58 5 whereby it appears, that the Objedls 
will be magnified about 38 times. To which proportion is 
very confentaneous, an Obfervation of the Crown on the 
weather-cock,about 500 feet diftaBr,For the fcheme , 
repref^nts it bigger ;by 2i timqs in diameter, when feen 
through, 
