no Sir George Shuckburgh's Account 
clock, or by a star out of the equator, and making proper al- 
lowance for the declination, in the proportion of the radius to 
the co-sine : or, edly, by means of the equatorial circle and a 
fixed land object ; and here the quantity must be diminis ed 
in the same ratio of the radius to the sine of the polar ins- 
tance. I have made use of both methods, as a confirmation 
of each other, and find the interval, which is equal in the 
three wires of my telescope, to be 7' 3 4/', 5 = 30", 3 sidereal 
time ; and these three wires divide the diameter of the field 
very nearly into four equal parts. 
(26.) Second and third adjustment ; the hanging level. By 
means of its proper handle u, move the declination circle 
about its axis, till the bubble of the hanging level /, m, rests 
true between the indexes, there fix it by the clamp w, re- 
verse the level, by taking it out of its pivots, and turning it 
end for end ; if the bubble now stand true, the level is ad- 
justed ; if not, correct \ the error by the declination handle, 
and the other \ by the small screw at the bottom of the level ; 
then reverse the level, and repeat this* operation till it does. 
The level, or rather a tangent to its curvature at its middle, 
will be parallel to the axis, on which it swings ; and both will 
be horizontal. At this time look through the telescope, and 
see what land object is covered by the horizontal wire ; now 
invert the telescope, by turning it 180° round the declination 
axis, and 180° round the polar, and bringing the level true, it 
will then point to nearly the same place ; and if exactly the 
same object as before be now covered by the horizontal wire, 
the axis of the level is adjusted parallel to the line of colli- 
mation, in a vertical direction ; if not, correct half the error 
by the little capstan screw at the bottom of the cock, or arm. 
