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THE HONGKONG GOVERNMENT GAZETTE, 17TH APRIL, 1886.
GOVERNMENT NOTIFICATION. No. 132.
The following Notice from the Director of the Observatory is published for general information.
By Command,
Colonial Secretary's Office, Hongkong, 17th April, 1886.
FREDERICK STEWART,
Acting Colonial Secretary.
ON THE PRACTICAL USE OF THE METEOROLOGICAL SIGNALS.
The utility of the Meteorological Signals hoisted at Tsimshatsui is confined to the shipping and to those interested in ships about to leave the harbour or out in the China Seas. The Colony itself is warned by means of the typhoon gun.
When the red drum is hoisted steamers if bound for northern, western or southern ports should lose no time in starting and may then expect more or less fine weather. Steamers bound for the Philippine Islands should take precautions to avoid the typhoon and observe the rules given in my notice of the 11th May, 1885. Sailing vessels if bound for western or southern ports should lose no time in starting, but if bound for northern or eastern ports they should remain in the harbour awaiting further information, as they may expect to encounter calms or contrary breezes after starting, even if the wind is westerly at the time.-The day after the drum being hoisted the information contained in the China Coast Meteorological Register issued from here should be considered, taking into account that the rate of progress of typhoons E or SE of Hongkong is generally between 6 and 14 miles an hour.
When the red cone pointing upwards is hoisted SW winds may be expected and ships leaving the harbour are not likely to run any risk from the typhoon, but sailing vessels bound for the north should start as soon as convenient, so as to benefit by the favourable SW breeze.
When the red cone pointing downwards is hoisted ships desirous of avoiding bad weather should remain in port till the barometer begins to rise, when danger from the typhoon is past.
When the red ball is hoisted ships starting for northern, southern or eastern ports may expect breezes from E round by S to SW. Those starting for western ports run no risk as long as they manage to keep their barometer rising. If it should happen to fall, they should heave to and subse- quently, if necessary, take refuge in some typhoon harbour, but this will rarely occur.
Vessels in the China Sea are generally enabled by observing the rules given in the notices of the 11th May, and the 16th July, 1885, to avoid running into typhoons, that may be encountered.-In the former notice the following rule is given:
“The whereabout of the centre of a typhoon may, in the China Sea, be ascertained by the rule:-stand with your back to the wind, and you will have the centre on your left side, but between two and four points in front of your left hand. There are however certain exceptions to this rule. Thus there often blows a steady Easterly gale along the southern Coast of China, when a typhoon is crossing the China Sea, and the gale blows often steady from North-East about the northern entrance to the Formosa Straits, when there is a typhoon in a more southern latitude.”
and an illustration of this rule is contained in the Weather Report for August, 1884, published on the 3rd April, 1885.
Further researches have shown, that in the Philippine Islands and along the Coast of China as far north as 24° latitude when you stand with your back to the wind in a typhoon, you will probably have the centre nearly 4 points in front of your left hand, but on the open sea far from any shore you will generally have it about 3 points in front of your left hand when your ship is in front of the centre of the typhoon, and more than 3 points in front of your left hand, behind the centre. Above 25° latitude the angle will probably be found to be between 2 and 3 points. It appears to be smaller the greater the distance from the nearest shore and the greater the latitude. At some distance behind the centre the wind blows generally straight towards it.
W. DOBERCK, Government Astronomer.
Hongkong Observatory, 11th April, 1886.
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