162 
HINTS TO TRAVELLERS. 
To find the Error of the Watch by Equal Altitudes of a Star. 
June 30th, 1899, a Scorpii (.Antares ) had equal altitudes at the 
undermentioned times. Longitude 26° 40" E. 
East Times. 
West Times. 
H. M. S. 
4 48 30 
4 49 3 1 
4 53 2 
4 55 14 
4 56 20 
5) 262 3 7 
4 52 3i'4 
Star East of Meridian 
Star West ,, 
Time by Watch of Star’s transit 
H. 
M. 
s. 
4 
52 
31*4 
II 
I 
46 
i5 
54 
17-4 
7 
57 
8-7 
Sidereal Time at Mean Noon (p. ii. k.a.). 
Acceleration (Table XXXI.) for Longitude in time 4- if West Longitude, — if East 
Longitude . 
Reduced Sidereal Time. : 
Star’s R.A , which will also be R.A. of Meridian. ; 
Star’s R.A. (+24 hours if necessary)—Reduced Sidereal Time .. 
m. s. 
Further reduced by Retardation (Table j -2 jt oms “ 1 1 
XXXII.) .. •• •• l 14 secs. = *04] 
Mean Time of Star’s Transit 
Time by Watch of Star’s Transit 
Error of Watch slow on Local Time 
H. 
M. 
s. 
IO 
57 
54 
IO 
59 
3 
11 
1 
11 
II 
4 
48 
II 
5 
54 
) 55 
8 
50 
11 
1 
46 
H. 
M. 
s. 
6 
33 
20-77 
“ 
17*53 
6 
33 
3*?4 
16 
23 
I7*i5 
9 
50 
13-91 
- 
I 
56*70 
9 
48 
37-21 
7 
57 
8-7 
1 
51 
28-5! 
Equal Altitudes of a Star on the same side of the Meridian , on different 
nights.— Observe the altitude of a star at any time, note the time and 
the altitude. After an interval of some days—for example, four days— 
set the index io the altitude noted, and take the time when the star 
attains it; then, as a star comes to the meridian exactly 3m. 55*91s, 
earlier every day, multiply this interval by the number of days elapsed, 
and subtract the product from the time when the first altitude was 
taken; the result will be the time the watch should show. Any difference 
between this result and the time the watch shows is the error for the 
interval, which, divided by the number of days, gives its daily rate; 
thus, if a watch showed 9h. 50m. 8s., when an observation of a star was 
