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TABLE SHOWING THE DIRECTION, DURATION AND VELOCITY ·
OF THE WINDS DURING 1887,-(Continued.)
Months.
Direction.
hours.
Duration in
Velocity in
Miles per hour.
Months.
Direction,
Duration in
hours.
Velocity in
Miles per hour.
SEPTEMBER,
N.
34
9-7
NOVEMBER,...
N.
144
12-8
N.E.
78
24-4
N.E. 158
11.6
E.
300
23.0
E. 318
15.8
S.E. 103
23.3
S.E.
47
11.0
S.
27
13.9
S.
1
2.0
S.W. 17
11.5
S.W.
2
8.0
W.
81
9.8
W.
12
6.2
N.W.
31
12-5
N.W. 10
6.6
Calm
49
0.5
Calm
28
0-7
OCTOBER........
N. 153
14-4
DECEMBER,.
N. 198
11.5
L
N.E.
164
12-8
N.E. 120 10:5
E.
288
16.1
E.
317 15.7
S.E.
69
8.9
S.E. 37
8.6
S.
16
3.8
S.
4.0
S.W. 3
6:0
S.W.
6
9.5
W.
10
5.3
W.
31
8.1
N.W. 6
4.8
N.W.
6.2
Calm 35
0.6
Calm 22
0.8
TIDES.
The tides in the harbour of Hongkong are semi-diurnal but considerable difference often exists between the heights of two consecutive tides, the higher being called the "superior" and the lower the "inferior" tide.
The difference in height of superior and inferior tides depends mainly upon
the moon's declination either north or south of the equator.
At the times of the moon crossing the equator the tides are equal.
The maximum range of tide may be taken as eight feet and the highest water under ordinary circumstances as 8 feet above Ordnance Datum and the lowest 1 foot below that Datum.
Tidal Observations.-With a view to ascertaining the general effect of the tidal currents at the points proposed for the sewer out-falls, i.e., Belcher's Point to the west of the city and North Point to the east, I made in conjunction with Mr. Jas. SAMPSON of the Public Works Department several float experiments on the 27th and 28th of February last during the North East Monsoon, and again on the 21st and 22nd of August during the South West Monsoon.
The floats used consisted of wooden buoys conical in shape, five feet in height and two feet in diameter from which were suspended wrought iron vanes 4 feet by 1 foot 6 inches of T shape construction and so designed as always to keep the larger surface of the vane square to the current. The total weight of a float was 236 lbs. and the depth of the vane below the surface of the water was about 7 feet.