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Instructions for keeping the Meteorological Log. Observations should be made every four hours, and the latitude and longitude of the vessel
More or less persistent SW winds, at times accompanied by thunderstorms, may when the red cone pointing upwards is hoisted, and ships leaving the port are not likely to run an risk from the typhoon. Sailing vessels bound for the north should start as soon as possible so as inhould be entered at each observation, benefit by the southerly breezes to run through the Formosa Channel, and avoid the way round Formosa. By following the latter route a sailer, moreover, runs the risk of falling in with the next typhoon east of Formosa, particularly during the mouths of August and September.
A cone pointing downwards usually implies fresh E veering to SE winds in Hongkong. As sug a typhoon may travel N and NE, the master of a vessel desirous of avoiding bad weather shoul consult the latest weather-intelligence or remain in port till the barometer rises.
Then the dange is past.
If convenient an observation should be made in or near Hongkong.
Observations are required between 10° South and 45° North latitu le and between Singapore and
E of Greenwich.
When a mercurial barometer real the thermometer attached to it is also entered, When an aneroid is read no thermometer reading should be entered. Force of wind is given from 0 to 12, and weather in Beaufort's initials.
When a ball is hoisted ships starting for northern, eastern, or southern ports may expect breezes from E round to S and SW. Those starting for western ports run no risk as long as the glasse in China" published in 1883 by the writer, may be consulted. continues to rise. Should it ever happen to fall: heave to and, if necessary, take refuge in a typhoo anchorage such as Saint John's harbour.
For further particulars the “Instructions for making Meteorological Observations prepared for
4.
The forms are forwarded free through British Post Offices in China if addressed on service. hey should be posted as soon as convenient after the vessel enters Hongkong harbour, Vessels bound for London from ports in the China Sea should post the forms in Singapore.
Mr. Fico has analysed his weather-forecasts for 1896 with the following results :- The results for wind direction, force, and weather are treated separately in the first instane The forecast wind direction is considered successful if the wind at Gap Rock blows the greater par of the 24 hours from a direction that does not differ more than 45° from the forecast (93 % were successful). Forecast wind force: light," is successful if the mean force registered at Gap Rock is light breeze, or if the wind force does not reach the force of a moderat breeze; moderate," if the mean is a moderate breeze, or if the wind force exceeds a light breeze and falls short of a strong breeze; "fresh," if the mean is a fresh breeze, or if the wind force exceeds a gentle breeze and fallin short of a moderate gale; "strong" if the mean is a strong breeze, or if the wind force exceeds moderate breeze and falls short of a fresh gale; "gale," if it blows more than 10 miles per hour Gap Rock (93 % were successful).
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Success 67 %, partial success 30 %, partial failure 2 %, total failure 1 %. Following the method used in meteorological offices and taking the sum of total and paris success as a teasure of success, and the sum of total and partial failure as a measure of failure, find finally that :--
97% of the weather-forecasts were successful.
In 1896 the total number of days' observations made on board 325 ships and forwarded to this Observatory was 18,541 (counting separately those made on board different ships on the saine day).
The surest of all warnings is furnished by the standard barometer on shore and the compensated eroid on board ship; you are all right if you can put your vessel on the tack that will keep your arometer rising. But in order to understand the indications of the immeter you will have to keep regular meteorological register. The master of a vessel who does not look at his aneroid till he is a typhoon, does not derive half the benefits from his observations that he would have enjoyed had be watched it beforehand. He might perhaps have avoided the weather he is now experiencing, or even have benefited by the favourable winds and sailed round the typhoon. No doubt, the time is approaching when underwriters will stipulate that the indications of an anëroid or a marine barometer must be regularly registered on board a vessel insured by them.
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The amount of success attached to the firing of the typhoon gun to in licate local gales has determined according to the method adopted at meteorological offices at home. According to method of counting, the storm-signal is justified it followed by a gale of force 8 and upwards will 48 hours at a place near sea-level within 50 miles of the place where the signal is hoisted. Ith failure because too late" if it blows a strong gale (force 9) before the signal is hoisted. Accusing to this way of counting, a failure has to be recorded every time the gun is not fired during the winka for a
“Norther," although we did not presume to forecast those.
The weather is successful when fine" is forecast if the mean amount of clouds is below 7-tents of the whole sky, if sunshine or starlight prevails, and when it does not rain more than one hour « On the other hated it would not be fair to ask the mariners to keep complete meteorological of twenty-four; when "fair, cloudy," if the amount of clouds exceeds 3-tenths and it does not na records, such as are kept in the lighthouses out here. Some seamen have a taste for this kind of more than one hour; when showery," if it rains at intervals and is fair at intervals; when "we work and make very useful and fairly accurate observations, but, for instance, the readings of dry and rainy" if it rains more than 4 hours (77% were successful). Counting days on which all the damp bulb thermometers taken on many vessels are of very little use. elements were correctly forecast as success, those when two elements were justified and one filed The tube of the marine barometer has to be so much contracted to stand the incessant pumping as "partial success," those when one element was justified and two failed as "partial failure," and danger of breakage, that the instrument is sluggish and often reads half an inch or more too high those when all elements failed as "total failure," we have :-
near the centre of a typhoon. Some cheap woolen barometers cannot be registered below a certain height, the cistern being too small to hold the mercury that comes out of the tube and there is the objection to wooden mercurial barometers that the readings cannot be accurately reduced to nezing point and the temperature correction is larger than in case of instruments made of brass, Of course, some cheap auëroids are no better, and even a first class compensated instrument requires to be thoroughly verified, as the scale is never quite correct and the readings depend somewhat upon the temperature and in a manner different for each single instrument, so that general tables for correcting freezing point are not available, but they act more quickly than the marine barometer, and for use board ship the instrument that is quickest in its indications must be preferred. The objection to use of the aneroid is founded on the fact that its inflex-correction changes gradually; but then this can be determine.l and allowed for by reading it off as often as the vessel enters a
port, such as Hongkong, where correct meteorological observations are constantly being made.
The best hours for making observations are 4 a.m., 8 a.m., etc., up to midnight inclusive. From 4 a.m, to 10 am, the barometer is rising, falling from 10a.m. to 4 p.m., rising from 4 p.m. 10 p.m., and falling from 10 pan. to 4 a.m. It reads highest at 10 a.m. and lowest at 4 The daily variation is twice as great in midwinter as it is in midsummer. During the approach of a phoon this regular daily variation may be masked, but it goes on all the same and must be taken into count when the barometer begins to fall before a typhoon. Thus if it has fallen a certain amount between 10 a.m, and 4 p.n, you must subtract the normal descent between these hours in order to There was 75% of success conning all the gales and all the times the gun was fired, or 831ow how much of the fall is due to the approach of the typhoon, and if it were between 4 p.m. and success if the "northers" be left out of account. This compares favourably with the percentage
p.m. that it full, you must add the norinal rise for the same purpose. success in the British Isles 58% only of which are justified by subsequent gales of force 8 and upward (mean of the 10 years 1884-93 inclusive). This leaves out of account the fact that in those isolate instances, where the gun was not fired, warning was given by notices issued and of late years, lanterns hoisted.--During the first eight years the gun was fired when the wind blew 37 miles hour on an average, while during the past four years it was fired when the wind blew only 2fferent varieties of typhoons, when a couple of hundred tracks were available.
In 1886 I expressed the hope that it might be possible to construct average paths of all the per hour on an average. This shows an improvement with the increase of staff in the Observaffected ou the basis of 244 typhoons, registered during the past 13 years, or on an average 19 This has just been that took place in the meantime, and with the increase in the number of telegraphic reporting station phoons per year. They are distributed among the different months of the year as follows: January Detailed particulars concerning every typhoon that occurred during the past thirteen years and e
February 9, March 1, April 4 (2 per cent), May 10 (4 pc), June 24 (10 p.c.), July 45 (19 p.c.), warning issued have been published in the "Government Gazette" and in the "Observations a Researches" issued yearly from here.
st 43 (18 p.c.), September 57 (23 pc.), October 31 (18 p.c.), November 22 (9 p.c.), December
Ju
The typhoon gun has been fired 27 times one round, since the Observatory was started on 1st January, 1884, ze., during the past 13 years. During the same period it has 30 times blown gale of force 8 and upwards: Once in February (norther), once in June (typhoon), 5 times in (typhoons), 3 times in August (typhoons), 11 times in September (typhoons), 7 times in Octal (typhoons), and twice in December (northers).
$4-ON THE DIFFERENT CLASSES OF TYPHOONS AND THE SEASONS OF THE YEAR IN WHICH THEY APPEAR.
(2 pc.).
p.in,
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