15
If the wind has veered very much between the two observations, this difference in the valuesof D 2 and the consequent difference in the storm’s direction determined therefrom may not beserious, hut if the wind has changed only a few points said difference might easily prove disastrousto the steamer.
The statements concerning the effect of the corrections for oscillation are further illustratedand confirmed by the table given at the end of this section.
TABLES OF CORRECTIONS TO Pi AND P 2 FOR DAILY OSCILLATION.
I. MANILA.
[120° 58' east of Greenwich; 14° 35' north latitude.]
Hour.
January.
February.
March.
April.
May.
June.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Miiii-
meters.
Inches.
Milli-
meters.
i
a.
m_
—0.
006
—0.
2
—0.
007
—0.
2
—0. 010
—0.3
—0.
012
—0.3
—0. 010
—0.3
—0.
Oil
—0.3
2
a.
m_
0.
007
0.
2
0.
005
0.
1
0. 004
0.1
0.
002
0.1
0.002
0.1
0.
001
0.0
3
a.
in
0.
017
0.
4
0.
014
0.
4
0.011
0.3
0.
Oil
0.3
0. 010
0.3
0.
009
0.2
4
a.
m_
0.
016
0.
4
0.
014
0.
4
0. 013
0.3
0.
010
0.3
0.010
0.3
0.
Oil
0.3
5
a.
m _
0.
007
0.
2
0.
006
0.
2
0. 005
0.1
0.
000
0.0
0. 003
0.1
0.
006
0.2
6
a.
m
—0.
006
—0.
2
—0.
010
—0.
3
—0.012
—0.3
—0.
014
—0.4
—0. 009
—0.2
—0.
005
—0.1
7
a.
m
—0.
024
—0.
6
—0.
028
—0.
7
—0. 032
—0.8
—0.
032
—0.8
—0. 025
—0.6
—0.
018
—0.5
8
a.
m_
—0.
042
—1.
1
—0.
044
—1.
1
—0. 047
—1.2
—0.
049
—1.2
—0. 036
—0.9
—0.
025
—0.6
9
a.
m_
—0.
053
—1.
3
—0.
056
—1.
4
—0. 056
—1. 4
—0.
055
—1.4
—0. 041
—1.0
—0.
029
—0.7
10
a.
m
—0.
047
—1.
2
—0.
054
—1.
4
—0. 050
—1.3
—0.
047
—1.2
—0. 037
—0.9
—0.
026
—0.7
11
a.
m_
—0.
031
—0.
8
—0.
037
—0.
9
—0. 037
—0.9
—0.
033
—0.8
—0. 024
—0.6
—0.
015
—0.4
Noon
—0.
007
-0.
2
—0.
013
—0.
3
—0. 013
—0.3
-0.
012
—0.3
—0. 006
—0.2
—0.
002
—0.1-
i
p-
m_
0.
024
0.
6
0.
018
0.
5
0. 018
0.5
0.
021
0.5
0.020
0.5
0.
018
0.5
2
p-
m_
0.
048
1.
2
0.
044
1.
1
0. 046
1.2
0.
048
1.2
0. 043
1.1
0.
035
0.9
3
p-
m_
0.
061
1.
5
0.
061
1.
5
0. 064
1.6
0.
065
1.7
0. 057
1.4
0.
049
1.2
4
P .
m
0.
056
1.
4
0.
061
1.
5
0. 067
1. 7
0.
070
1.8
0.062
1.6
0.
052
1.3
5
p-
m .
0.
041
1.
0
0.
050
1.
3
0.057
1.4
0.
063
1.4
0. 054
1.4
0.
044
1.1
6
p-
m_
0.
026
0.
7
0.
036
0.
9
0. 041
1.0
0.
042
1.1
0.033
0.8
0.
028
0.7
7
p-
m_
0.
008
0.
2
0.
020
0.
5
0.023
0.6
0.
022
0.6
0. 014
0.4
0.
010
0.3
8
p-
m_
—0.
008
—0.
2
0.
001
0.
0
0.003
0.1
0.
002
0.1
—0.004
—0.1
—0.
008
—0.2
9
p-
m_
—0.
020
—0.
5
—0.
014
—0.
4
—0. 016
—0.4
—0.
017
—0.4
—0.022
-0.6
—0.
024
—0.6
10
p-
ni_
—0.
024
—0.
6
—0.
022
—0.
6
—0. 027
—0.7
—0.
032
—0.8
—0.034
—0.9
—0.
035
—0.9
11
p-
m_
—0.
022
—0.
6
—0.
023
—0.
6
—0. 030
—0.8
—0.
033
—0.8
—0. 035
—0.9
—0.
038
—1.0
Midnight_
—0.
017
—0.
4
—0.
019
—0.
5
—0. 022
—0.6
-0.
022
—0.6
—0. 023
—0.6
—0.
027
—0.7
July.
August.
September.
October.
November.
December.
Hour.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
Inches.
Milli-
meters.
i
a.
m_
—0.
008
—0.
2
—0.
010
—0.
3
—0. 007
—0.2
—0.
002
—0.1
—0. 003
—0.1
—0.
006
—0.2
2
a.
m _
0.
005
0.
1
0.
005
0.
1
0. 007
0.2
0.
011
0.3
0. 012
0.3
0.
009
0.2
3
a.
m _
0.
013
0.
3
0.
014
0.
4
0. 016
0.4
0.
019
0.5
0.022
0.6
0.
020
0.5-
4
a.
ni
0.
015
0.
4
0.
016
0.
4
0. 018
0.5
0.
020
0.5
0. 022
0.6
0.
018
0.5
5
a.
ni
0.
012
0.
3
0.
012
0.
3
0. 012
0.3
0.
013
0.3
0. 013
0.3
0.
010
0.3
6
a.
m__
0.
001
0.
0
0.
004
0.
1
0. 002
0.1
—0.
004
—0.1
—0. 004
—0.1
0.
003
0.1
7
a.
in
—0.
011
—0.
3
—0.
010
—0.
3
—0. 013
—0.3
—0.
020
—0.5
—0. 021
—0.5
—0.
021
—0.5
8
a.
m_
—0.
020
—0.
5
—0.
023
—0.
6
—0.029
—0.7
—0.
034
—0.9
—0. 036
—0.9
—0.
041
—1.0
9
a.
m_
—0.
026
—0.
7
—0.
030
—0.
8
—0. 035
—0.9
—0.
043
—1.1
—0.045
—1.1
—0.
048
—1.2
10
a.
m_
—0.
024
—0.
6
—0.
027
—0.
7
—0. 033
—0.8
—0.
040
—1.0
—0.040
—1.0
—0.
042
—1.1
11
a.
in_
—0.
017
—0.
4
—0.
020
—0.
5
—0.024
—0.6
—0.
024
—0.6
—0. 024
—0.6
—0.
027
—0.7
Noon
_
—0.
005
—0.
1
—0.
007
—0.
2
—0. 004
—0.1
—0.
002
—0.1
—0. 003
—0.1
—0.
005
—0.1
i
p-
in
0.
014
0.
4
0.
016
0.
4
0. 021
0.5
0.
023
0.6
0.024
0.6
0.
025
0.6
2
p-
in.
0.
029
0.
7
0.
033
0.
8
0. 040
1.0
0.
044
1.1
0.044
1.1
0.
047
1.2
3
p-
m
0.
040
1.
0
0.
044
1.
1
0. 049
1.2
0.
053
1.3
0. 051
1.3
0.
057
1.4
4
p-
m_
0.
044
1.
1
0.
047
1.
2
0. 047
1.2
0.
048
1.2
0. 047
1.2
0.
052
1.3
5
p-
m_
0.
038
1.
0
0.
040
1.
0
0. 038
1.0
0.
036
0.9
0. 034
0.9
0.
037
0.9
6
p-
m _
0.
024
0.
6
0.
026
0.
7
0. 022
0.6
0.
023
0.6
0. 021
0.5
0.
022
0.6
7
p-
HI_
0.
007
0.
2
0.
008
0.
2
0. 005
•0.1
0.
004
0.1
-0. 002
0.1
0.
004
0.1
8
p-
m__
—0.
009
—0.
2
—0.
009
—0.
2
—0. 012
—0.3
—0.
015
—0.4
—0.016
—0.4
—0.
014
-0.4
9
p-
in_
-0.
023
—0.
6
—0.
026
—0.
7
—0. 028
—0.7
—0.
029
—0.7
—0.027
—0.7
—0.
025
—0.6
10
p-
m_
—0.
035
—0.
9
—0.
037
—0.
9
—0. 037
—0.9
—0.
033
—0.8
—0. 030
—0.8
—0.
028
—0.7
11
p-
m_
—0.
035
—0.
9
—0.
036
—0.
9
—0. 033
—0.8
—0.
030
—0.8
—0. 027
—0.7
—0.
024
—0.6
Midnight_
—0.
024
—0.
6
—0.
024
—0.
6
—0. 020
—0.5
—0.
020
—0.5
—0. 017
—0.4
—0.
014
—0.4