XI 
The Mi cr of cope explained, 
you are in, to the point of the flower-de-luce at K, then 
tighten the fcrew at f, to fix the arch ; by this means 
the axis IL upon which the mirror- M N turns, will 
be properly elevated above the horizon of the place. 
Screw the part b b of the tube K, fig. 4. into the 
infide of the top of the box A D F, fig. 6. there being 
a brafs plate at F prepared for its reception : then fcrew 
the little tube M to the end N of the Microfcope, N P, 
fig. 5. and put an objedt between the plates ed, gh, as 
before directed in the defcription of the folar apparatus. 
Now fet the camera upon a table placed nearly level 
in the fun fhine, turn it about that the direction of the 
fide E B may be nearly in the meridian ; if you have no 
meridian line, a fquare magnetic compafs box T V ap¬ 
plied in the direction of the fide C O, but to the back 
of the camera which is oppofite and parallel thereto, 
and perpendicular to the fide E B. Now turn the whole 
J nftrument together with the compafs box, until the 
needle refts over the degree of its variation at the place 
you are at *, then the axis I L will be nearly parallel to 
the axis of the equator, and give an equatorial motion 
to the mirror M N. 
Put a (heet of paper into the camera, and fix it there 
by wafers, wax, or needle points fixed in very fmall 
brafs buttons. Elevate or deprefs the mirror M N, by 
taking hold of it at N, and if neceflary, turn it a little 
fideways, until you obtain a round fpot of light upon the 
paper, by looking at it through the apperture, a be. 
Then flip the tube I, together with the microfcope 
N P. fig. 5. with an objedt applied to it, into the tube 
K of the folar apparatus, fig. 4. Turn the milled head 
fcrew O, of fig. 5. to bring the magnifier to its due 
focal diftance, from the paper on the infide of the bot¬ 
tom 
* Note, the variation, of the magnetic needle in London, 
is about 21 degrees from the north towards the weft. 
