t 5 r 5 ] r 
horizontal Thread ; or (if the Sun be too low) till 
that of the perpendicular Thread in one Stile, or the 
Light through the Slit in the other, falls upon the 
Line on the Index Bar, or vibrates to an equal Di- 
flance on each Side of it, gently touching the Box, 
if it vibrate too far : Obferve at the fame time the 
Degree marked upon the brafs Edge by the catgut 
Line. In counting the Degree for the Azimuth, 
or any other Angle that is reckon’d from the Meri- 
dian, make ufe of the outward Circle of Figures 
upon the brafs Edge, and the Situation of the Index 
Bar, with regard to the Card and Needle, will al- 
ways direct upon what Quarter of the Compafs the 
Object is placed. 
But if the Sun does not fin i n e out fufficiently 
ftrong, place the Eye behind the narrow Slit in one 
of the Stiles, and turn the wooden Box about, till 
fome Part of the horizontal or perpendicular Thread 
appears to interfcct the Centre of the Sun, or vibrate 
to an equal Diftance on each Side of it, uftng 
fmoked Glafs next the Eye, if the Sun’s Light is 
too ftrong. In this Method another Obferver will 
be generally neceftary to note the Degree cut by 
the Nonius, at the fame time the fiift gives notice 
that the Thread appears to fplir the O'ojed. 
From what has been faid, the other Obfervations 
will be eafily performed j only in cafe of the Sun’s 
Amplitude, take care to number the Degiee by the 
Help of the inner Circle of Figures on the Card, 
which are the Complements of the outer to 90, 
and confequcntly fhew the Diftance from Eafl or 
Weft. 
U u 11 The 
