'The Transactions of the Bombay Geographical Society. From January 1863 to December 1864. (Edited by the Secretary.) Volume XVII.' [‎5] (166/524)

BOMBAY TIDAL OBSERVATIONS FOR 1861. 5
the moon’s mass ^ of the earth’s—results agreeing very closely with
those derived from the upper transit tides alone.
Again, taking the results of the observations belonging to the transits
between 6-30 a.m. and 6-30 p.m. only, their mean value is found to
he 49?/?., and the time of transit for mean acceleration is found to be
50| minutes, corresponding to an elongation of 12° 37 / ;—whence, again,
“ "426 — 2^3450 and the ([ s mass 7(3.2 •
By three different arrangements then, we derive the mean or correct
ed establishment of the port about = 49 minutes* (the vulgar establish
ment being —32m.) ; the corresponding elongation of the moon being
about 12° 40' ; the ratio of the forces of the sun and moon |= *428,
or the moon’s force, not exceeding 2"38 times the sun’s, and the moon’s
mass Ag. The age of the tide may likewise be roughly determined to
be about 1*1 day. Now, in Professor Orlebar’s/ormw/tf?, the values
assigned to these quantities are as follows: —The mean establishment
he fixes at —58m., the moon’s elongation 17° 30', the moon’s attractive
force 2-60 times the sun’s, and the moon’s mass ^ of that of the
* The late Mr. Dessiou prepared a table of the Semi-menstrual Inequality found
ed on observations at London, Liverpool, Pembroke, Ramsgate, Sheerness, Ports
mouth, Plymouth, Brest, and St. Helena, of which the following is an abstract: —
Moon’s
Transit.
Semi-mens.
Inequality.
Moon’s
Transit.
Semi-mens.
Inequality.
Moon’s
Transit.
Semi-mens.
Inequality.
h.
m.
h.
m.
h.
m.
h.
m.
h.
771.
h.
771.
0
0
— 0
0
4
0
—0
55
8
0
—0
15
0
30
—0
6
4
30
— 1
0
8
30
—0
1
1
0
-0
13
5
0
— 1
3
9
0
+0
9
1
30
—0
20
0
30
— 1
5
9
30
+0
15
2
0
—0
28
6
0
— 1
3
10
0
+0
16
2
30
— 0
36
6
30
— 0
56
10
30
4-0
15
* 3
0
—0
43
7
0
—0
44
11
0
+0
11
3
30
—0
49
7
30
—0
30
11
30
-f-0
6
If then the tides at Bombay have a similar degree of semi-menstrual inequality,
we might find the approximate time of the tide by applying the inequality, taken
from the above table, to the time of the moon’s transit, and then subtracting 49m.
Corrections would require to be applied for the variations of the declination and
parallax of the sun and moon, &c.