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Compafs was contriv'd, and has by Experience been 
found effedual. It would be needlefs to give a De- 
fcription to fuch as have the Inftrument before them, 
and we (hall therefore only (hew the Manner of ufing 
ir, and that as briefly as may be, which take as fol- 
lows : 
i :Ji 7 The Inftrument muft be redified, or fitted for 
Obfervation, by turning it about till the four Car- 
dinal Points, that are hung upon the Centre-pin, 
agree with the four Cardinal Points on the Chart, at 
the Bottom of the Box : Then will the Needle, that 
fhews the Magnetic Meridian, ftand at no Degrees, 
and the Eaft and Weft Points at 90 Degrees, on the 
.graduated Circle within the Box; and in this Situa- 
tion it muft be kept, as near as may be, during the 
whole time of the Obfervation. 
idly 7 Let the Index of the Quadrant be placed to 
that Degree of the Arch, on the Rim of the Box, 
which the Obferver judges to be nearly equal to the 
Height of the Sun or Star whofe Azimuth is fought ; 
for by this means the Objed will be more readily 
found. 
3 dly 7 Turn the Quadrant round towards the Sun 
or Star, till it appear upon the vertical Hair within the 
Telefcope, to an Eye looking through the fmall Hole 
or Sight; and then Aide the Index a little upward or 
downward on the Arch, till the Objed by this means 
be brought to coincide or touch the vifible Horizon. 
Laftly , The Degrees and Minutes then mark'd 
by the Index upon the Arch of the Quadrant, will fhew 
the Altitude of the Objed, which will always be the 
fame, whether the Inftrument is in Motion or at Reft $ 
at the feme time the Degree cut by the Index on the 
ho- 
