C IC9 ] 
To adjuft the inftrument for obfervatlon, the firfl: 
thing to be done is to make the horizontal plate D 
level, by means of the fpirit level, and the three ad- 
juring fcrews at the bottom of the fland ; this being 
done, move the equatorial plate either with or without 
the latitude handle, until the index on the quadrant 
points to the latitude of the place; and then the e- 
quatorial plate will be raifed, to the elevation of the 
equator of the place, which is equal to the complement 
of the latitude (and which, if not known, may like- 
wife be found by this inftrument, as will appear 
hereafter) ; and thus the inftrument Is ready for 
oblervation. The manner of ufing this inftrument for 
the following obfervations, 1 fhall borrow in part 
from the words of the late ingenious Mr. Short, in 
his defcription of his equatorial telefcope*, which,, 
however, ditfers eflenfially in conftrudtion from this. 
To find the Hour of the Day, and the Meridian of- 
the Place. 
Firft, find from aftronomical Tables, the Sun’s 
declination for the day; and for that particular time 
of the day ; then let the declination femicircle to the 
declination of the Sun, taking particular notice whe- 
ther it is North, or South ; and fet the declination 
femicircle accordingly, you then turn about both the 
horizontal handle and equatorial handle, until you 
find the Sun precifely concentrical with the field of 
the telefcope ; if you have a clock or watch at 
hand, mark that inftant of time, and by looking upon, 
the equatorial plate and vernier index, you will' find; 
* Vide Phil. Tranf. Vol. XL. p. 242^. 
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