VARIATION or tue COMPASS. 255° 
be the variation. And if the magnetic be to the weftward 
of the true azimuth, the variation will be wefterly ; but if 
to the eaftward, the variation will be eafterly. 
If the time before the ftar’s paflage over the meridian 
be fome intermediate minute, or the latitude of the place 
fome intermediate degree, not found in the table, a pro- 
portional intermediate azimuth, by means of the differ- 
ences, muft be taken. 
The right afcenfion of the pole ftar annually increafes 
to feconds of time, and its polar diftance decreafes 20 fe- 
conds of a degree, therefore to its prefent right afcenfion 
(in 17855) viz. o" 49", muft be added one minute every 
year; and from its prefent polar diftance (1° 50’.5) one 
minute muft be fubtraéted, and a proportional part from 
all the numbers in the columns of azimuth, every three 
years.. The effect of aberration and nutation may be 
fafely negle@ted; as the error arifing from thefe caufes: 
can never amount to more than half a minute of a degree 
in azimuth. 
In computing the fun’s right afcenfion to the time of 
the ftar’s paflage over the meridian nearly, the following, 
little table will be ufeful. . 
Kk2 TABLE. 
