'The Transactions of the Bombay Geographical Society. From January 1863 to December 1864. (Edited by the Secretary.) Volume XVII.' [‎13] (174/524)

BOMBAY TIDAL OBSERVATIONS FOR 1861.
13
Or, the final results of the comparisons may he condensed, as in the
following table :—
E *
Differences between
Observations and
the results given
by the formula
and the Constants.
By Professor
Orlebar’s
formula.
Bv the First
C/
Constant,
-f 97u 31m.
By the
Second
Constant,
— 2k. 50m.
By the
Third
Constant,
—14^.59 m.
By the
Fourth
Constant,
—27/i.24m.
Om. to 12 m.
100 obs.
107 obs.
122 obs.
1 16 obs.
121 obs.
12 — 30
114
118
109
114
110
30 — 60
78
58
58
73
71
m
: !
60 — 90
2n 4 i
27)41
26)31
28)32
Vi
90 — 120
12 j
• 14 J
14 /
5 J
4 J
*1 .
120 — 150
2
9
4
1
1
«») ■
s
Ml
150 — 187
0
1
1
0
' 0
Mi
A 1 .
v¥
8!
No. of Obs.
335
335
335
335
335
M
V\
V
s
t
Average error
dt29m.
dzSO’Sm.
dt 2/’2m.
ih24‘6m.
dr 2 ,i'3m.
Thus, then, of the whole of the observations at the upper transit^
there are not above 45 per cent, even tolerably concordant with any
one of the methods of approximation; and excepting a few observa
tions at the times of new and full moon, it would evidently be
impossible to point out with accuracy the individual observations which
might be trusted within certain limits.* Thus, if we take the tides of
June 19th and 30th, 1861, the errors are as follows : —
Tide of 19th June. Tide of 30th June
By Professor Orlebar’s formula .. ..
late.
12 5m. late.
By the First Constant
a
109 „
By the Second Constant
«
CO
106 „
By subtracting 14A. 59m. from the "
2nd London tide after ...... j
j. 65
jj
OO
OO
v«
V*
By subtracting 27 h. 24m. from the '
3rd London tide after j
\ 57
OO
* The diagrams (shown to the meeting) best illustrate this. On each diagram
is laid down the course of the observed times of high-water throughout
one lunation, and also of the times as computed by Professor Orlebaf’s formula,
and by the application of each of the four constants to different tides at London
Bridge. The vertical distances between the line of the observations and any
of the lines of computation, show the errors of observation of the selected^ tides
according to the method chosen for comparison. The diurnal inequality will, no