F 9
The figures in the above table include the number of hours that night signals, corresponding to the day signals, were hoisted.
Formerly the red signals indicated that the centre of the typhoon was believed to be more than 300 miles distant, and the black less than 300 miles, the returns for 1912-1916 are therefore not strictly comparable with those for 1917. The latter suggest however that the use of the new local storm warning code has already saved the Colony a considerable amount of money. The loss incurred by the disorganisation of the work in the harbour, consequent upon the display of black typhoon signals, is not easy to estimate. It probably amounts to many thousands of dollars a day, however.
VI.—METEOROLOGICAL OBSERVATIONS FROM SHIPS, TREATY PORTS, &c.
Logs received. In addition to meteorological registers kept at about 40 stations in China, meteorological logs were received from 85 ships operating in the Far East. These logs, representing 3,767 days observations, have been utilised for verifying typhoon tracks. The corresponding figures for the year 1916 were 158 and 7,456.
No progress has been made with the construction of Pilot Charts owing to the absence on leave of the First Assistant.
Comparison of Barometers.—During the year about 600 comparisons of ships barometers have been made by means of observations taken when in harbour, and several direct comparisons of barometers for shipmasters and various persons in the Colony have been made at the Observatory.
On June 11, Mr. B. G. Tours, C.M.G., H.B.M. Consul at Ichang, brought an aneroid barometer to the Observatory to be tested. He had been making observations with it at altitudes of several thousand feet, while on a government mission through China. It was found that at a true pressure of 23.52 the barometer read 0.37 too high, and at 29.63 it read 0.61 too low. Mr. Tours was supplied with a table of corrections applicable to the readings of his barometer over different portions of the scale.
VII.—MAGNETIC OBSERVATIONS.
Absolute determinations of magnetic horizontal force and declination were made near the middle of each month with a Kew pattern magnetometer, Elliott No. 55, and of dip with a Kew pattern dip circle, Dover No. 71, four dip needles being used in rotation. A complete determination of horizontal force consists of one set of vibrations taken between two sets of deflections.
The mean values of the Magnetic elements for the years 1916 and 1917 were as follows:
1916 1917 Declination (west) 0° 13' 48" 0° 16' 16" Dip (north) 30° 51' 51" 30° 50' 22" Horizontal Force (C.G.S. unit) 0.37155 0.37163 Vertical Force (C.G.S. unit) 0.22205 0.22188 Total Force (C.G.S. unit) 0.43284 0.43282F 9
The figures in the above table include the number of hours that night signals, corresponding to the day signals, were hoisted.
Formerly the red signals indicated that the centre of the typhoon was believed to be more than 300 miles distant, and the black less than 300 miles, the returns for 1912-1916 are therefore not strictly comparable with those for 1917. The latter suggest however that the use of the new local storm warning code has already saved the Colony a considerable amount of money. The loss incurred by the disorganisation of the work in the harbour, consequent upon the display of black typhoon signals, is not easy to estimate. It probably amounts to many thousands of dollars a day, however.
VI.--METEOROLOGICAL OBESERVATIONS FROM SHIPS, TREATY PORTS, &c.
Loys received. In addition to meteorological registers kept at about 40 stations in China, meteorological logs were received from 85 ships operating in the Far East. These logs, representing 3,767 days observations, have been utilised for verifying typhoon tracks. The corresponding figures for the year 1916 were 158 and 7,456.
No progress has been made with the construction of Pilot Charts owing to the absence on leave of the First Assistant.
Comparison of Barometers.—During the year about 600 com- parisons of ships barometers have been made by means of obser- vations taken when in harbour, and several direct comparisons of barometers for shipmasters and various persons in the Colony have been made at the Observatory.
On June 11. Mr. B. G. Tours, C.M.G., H.B.M. Consul at Ichang, brought an aneroid barometer to the Observatory to be tested. He had been making observations with it at altitudes of several thousand feet, while on a government mission through China. It was found that at a true pressure of 2352 the baro- meter read 0 37 too high, and at 2963 it read 061 too low. Mr. Tours was supplied with a table of corrections applicable to the readings of his barometer over different portions of the scale.
VIL-MAGNETIC OBSERVATIONS.
Absolute determinations of magnetic horizontal force and declination were made near the middle of each month with a Kew pattern magnetometer, Elliott No. 55, and of dip with a Kew pattern dip circle, Dover No. 71, four dip needles being used in rotation. A complete determination of horizontal force consists of one set of vibrations taken between two sets of deflections.
The mean values of the Magnetic clements for the years 1916 and 1917 were as follows:-
Declination (west)
Dip (north)
Horizontal Force (C.G.S. uuit)
Vertical Force (C.G.S. unit)... Total Force (C.G.S. unit)
0 13 48
1916.
1917.
"
}
}}
0 16 16
30 51 51
30 50 22
087155
0-37163
0.22205
0-43284
0-22188
043282
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