22 ELUCIDATION OF THE PRECEDING TABLES,
Required the time of sun rising and setting at Glasgow in latitude 55° 52' JT,
ongitude 4° 16' W., on 17th May., 1855.
By a table of serai-diurnal arcs, the approximate time of sun's rising
and setting is —
Rising, 3 h. 56 m. Setting, 8 h 4 m.
Longitude in time of Glasgow, -|- 17 -4- 17
4 13 8 21
The sun's declination reduced to these times is 19° 12' and 19° 21', and the polar
distances are 70° 48' and 70° 39'. The horizontal refraction, less the sun's parallax,
is 33° 17' — 8 = 33' 9" -f- 90 = 90° 33', aud hence the following computation : —
Zenith distance, 90° 33' 90° 33'
Polar distance,... 70 48 co-secant 0-024855 70 39 co-secant 0-025252
Co-latitude, 34 08 co-secant 250944 34 08 co-secant 250944
195 29
195
20
97 44
sine 9-996023 97
40
sine 9-996100
7 11
sine 9-097065 7
07
sine 9-093037
~ 2)19-368887
~ 2)19-365333
sine 9-684443
eo-sine 9-682666
JI. M.
s.
H. M. S.
1 55
•2
4 4 50
2
3 50
8 9 40
Equa. time,.
3
53
Equa. time,..
3 52
Time of rising,.. 3 46 7 Time of setting, 8 5 48
Note. — The latitude of Glasgow is 55° 52' north, the longitude 4° 16' west of
Greenwich ; consequently there are 1 7 minutes of difference of time between the clocks
of Greenwich and the clocks at Glasgow, the Greenwich time being earlier. The
clocks of the United Kingdom are now generally adjusted to Greenwich time.
JAMES YUILLE,
Teacher of Mathematics, Navigation, and Nautical Astronomy,
56 Jamaica Street, Glasgow.