12 
THE REV. W. WHEWELL ON THE EMPIRICAL LAWS 
H . P . ... 
54'. 
55'. 
56'. 
57'. 
58'. 
59 '. 
60 '. 
61 '. 
Obs . .. 
Formula 
14-20 
14-02 
14-41 
14-42 
14-84 
14-82 
1522 
15-22 
15-63 
15-62 
16-02 
16-02 
16-43 
16-42 
16-66 
16-82 
We cannot compare this effect of parallax on the heights with the whole height of 
the tide, or with theory, from not having any observations of low water for this series 
of tides. 
The periodical part of the heights, as appears by the remainder of Table VII. (b.), 
whatever be the parallax, follows nearly the law of the mean, which has already 
been explained ; and the magnitude of the maximum differences does not appear to 
be steadily different for different H. P. In fact, theory would lead us to expect it to 
be the same in all these cases, because the amount of this inequality is 2 h , double the 
mean solar tide. 
20 . But it appears from the Table VII. (b.) that the time of moon’s transit, when the 
periodical inequality vanishes, is later for the larger parallaxes, and the maxima indi- 
cate the same change : the amount of the change is about 4 ra (p — 57), at the mean 
between the greatest and least values of the height. 
When ® ~ -f- 05 , the formula for the inequality becomes It! — h, which is the 
mean between the greatest and least values. In this case « = l h . Hence the value 
of a is 60 m + 4 ra (p — 57). 
Effect of the Moons Decimation. 
2 1 . The effect of the changes of lunar declination upon the tide will be found in 
nearly the same way as the effect of changes in the parallax. Mr. Lubbock’s 
Table XII. gives the intervals for each 3° of declination. By finding the mean of each 
column, and subtracting it from the column, we obtain the non-periodical and the 
periodical part respectively of the inequality as is done in Table XII. (a.) 
Table XII. (a.) 
[Intervals of times.] Mean of each column subtracted from the column. 
Decl 
0°. 
3°. 
6°. 
9°. 
12°. 
15°. 
18°. 
21°. 
24°. 
27°. 
Mean \ 
h m 
h m 
h m 
li m 
h m 
h m 
h m 
h m 
b m 
h m 
Interval J 
11 12-1 
11 11-0 
11 11-3 
11 10-4 
11 8-4 
11 6-5 
11 3-6 
11 1-2 
10 59-0 
10 55-6 
D ’sTransit. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
Remainder. 
0 30 
+ 10-0 
4 8-4 
4 8-8 
4 - 9-1 
+ 9*5 
4 - 10-8 
412-1 
412-3 
413-2 
413-6 
1 30 
- 7-1 
- 6-3 
- 5-6 
- 6-1 
— 5-5 
— 5-3 
- 4-6 
— 3-2 
- 3-8 
- 3-3 
2 30 
— 20-7 
— 20-4 
— 20-5 
— 21-1 
— 20-4 
- 20-5 
— 20-0 
— 20-8 
— 20-8 
- 20-6 
3 30 
— 33-0 
- 31-9 
— 32-7 
— 31-5 
— 33-0 
— 33-7 
- 30-4 
— 33-0 
— 34-4 
— 33-7 
4 30 
— 40-5 
— 41-2 
- 40-9 
- 40-3 
— 41-1 
— 42-2 
— 42-0 
— 43-3 
— 44-6 
— 45-7 
5 30 
- 37-6 
— 36-0 
— 37-2 
- 38-3 
— 40-2 
— 40-4 
— 43-4 
— 43-5 
— 45-7 
- 46-6 
6 30 
- 17-4 
- 17-2 
- 19-6 
— 20-7 
— 22-2 
— 23-1 
— 25-3 
- 26-9 
— 28-4 
- 31-7 
7 30 
+ 11-3 
+ 14-0 
+ 11-5 
+ 12-0 
4 - 10-0 
411-4 
4 8-6 
4 3-4 
4 9-3 
4 4-3 
8 30 
4 35-0 
+ 33-0 
+ 37-1 
4 - 34-3 
4 - 37-2 
4 36-4 
4 36-5 
4 - 39-7 
4 37-3 
4 40-9 
9 30 
+ 41-7 
+ 41-2 
4 - 44-7 
4 - 43-1 
4 - 42-2 
443-6 
444-1 
446-0 
4 46-6 
4 49-9 
10 30 
+ 36-0 
+ 31-8 
4 - - 34-7 
4 - 36-0 
4 - 38-5 
437-9 
4 38-5 
440-9 
442-1 
443-6 
11 30 
4 22-3 
+ 24-6 
4 - 21-9 
4 - 23-9 
+ 25-6 
425-6 
426-6 
4 28-2 
428-9 
4 30-0 
Greatest | 
DifT. / 
82-2 
82-4 
83-6 
83-4 
83-3 
85-8 
87-5 
89*5 
to 
to 
1 
96-5 
Excess 1 
above 82 J 
0-2 
0-4 
1-6 
1-4 
1-3 
3-8 
5*5 
7*5 
10-3 
14-5 
