Camera Obscura Microfcope , 23 
the Brightnefs of the Sun-fhine, depend the 
Sharpnefs and Perfection of your Image. 
Then putting theLooking-glafsG.through 
the Hole in your Window-ihutter, fatten 
the fquare Frame A. to the faid Shutter 
by its two Screws and Nuts 1. 1. 
This done, adjutt your Looking-glafs to 
the Elevation and Situation of the Sun, by 
Means of the jointed Wire PL together with 
the Cat-gut and fully, 3. 4. For the hrit 
of thefe raifmg or lowering the Glafs, and 
the other inclining it to either Side, there 
refults a twofold Motion, which may eafily 
be fo managed as to bring the Glafs to a 
right Pofition, that is, to make it reded: the 
Sun’s Rays direCtly through the Lens 5. 
upon the Paper Screen, and form thereon 
a Spot of Light exactly round 
As foon as this appears, fcrew the Tube 
C. into the Brafs Collar provided for it in 
the Middle of your Wood-work, taking 
Care not to alter your Looking-glafs: then 
fcrewing the Magnifier you chufe to em¬ 
ploy to the End of your Microfcope, in the 
* Though obtaining a perfect circular Spot of Light 
upon the Screen, before you apply the Microfcope, is a 
certain Proof that your Looking-glafs is -adjufted right, 
that Proof mull not always be expe&ed : for the Sun is fo 
low in Winter, that if it Ihines in a direct Line againll the 
Window, it cannot then afford a Spot of Light exadtly 
round. But if it be on either Side of you, a round Spot 
may be obtained even, in December* 
' " * ' ' ‘" ufual 
