261 SUP MENT TO THE HONGKONG GOVT GAZETTE OF 2810 MAR., 1885,
Table VIII shows the total distance traversed by, as well as duration and average velocity ce winds from bi-quadrantal points. The velocity is a maximum for E winds during which the trad and the monsoon blow together, and which also preponderate while typhoons are passing across th China Sea south of Hongkong, but there is a secondary maximum for SW winds, whose duration is however nearly a minimum.
Table IX shows particulars concerning the rainfall. It is plain, that the observers on Ston- Cutter's Island and at the l'eak neglect to measure the rain every day.
Table X contains particulars concerning different phenomena. Fog is at sen level noted only in spring. It is of course common at a higher level. Electric phenomena are most frequent in August, but most thunderstorms passed over the Colony in May. Some damage to property was caused by them. Unusual visibility of distant objects was most common in summer, when the air is moist and at the same time fog absent. Rainbows, which are so common in Great Britain and Ireland, are rarely seen here. The maximum frequency of halos coincides with the maximum frequency of typhoons.
Table XI shows the frequency of clouds of different forms. During January cum, and R-cum. prevail. In February R-cum and nim prevail. In March cum-nim is the usual cloud. In April cum again prevails and holds the ground till next February.-C, c-str and c-cum reach their maximum in the typhoon season, the latter form of cloud already in July.-Sm-cum are common during the last half year.
In January the lower clouds came from E, and the direction veered with increasing height, the highest clouds coming from W. In February the lower clouds came from E but occasionally also from W or SW, the highest from W. In March and April the lower clouds came from SE, and the direction veered with increasing height, the highest clouds coming from W. In May the lower clouds came partly from E and partly from SW, the highest from W. In June the lower clouds came from SE by E and the highest from WSW. In July the lower clouds came from SSE. The average direction of the higher clouds was then perhaps about NE, but their direction whence coining is evidently dependent upon typhoons. In August the lower clouds came generally from the portion of the compass between W, S and NE and the upper from the portion between WNW, N and SE. In September no average direction could be made out. It depends upon the typhoons. In October the lower clouds came from E and the highest from W. In November the lower came from E and the highest from different directions. In December the average directions could not be ascertained beyond doubt. It appears the lower clouds came from NE and the higher from SW or thereabout..
Clouds less than 2,000 feet above sea level were observed in January on 10 days, in February on 13 days, in March on 23 days, in April on 20 days, in May on 20 days, in June on 18 days, in July on 4 days, in August on 8 days, in September on 5 days, in October on 4 days, in November on 8 days and never in December. They were below 1,000 feet on one day in January, on 2 days in February, on 9 days in March, on 6 days in April and on one day in May."
Table XII shows the cloudiness, which is greater in the forenoon than in the afternoon, as appeared also from the sunshine-records. It reached its maximum in March, during which the sky" was almost continuously overcast, and decreased then slowly till the minimum in December. January the cloudiness increases abruptly.
In.
Table XIII shows the sea-disturbance (0-9), which is greatest in November and December and least in summer.
Table XIV shows the mean readings of the solar radiation maximum thermometers, which were carefully compared in January and have been reduced to the standard kept at Kew. The mean maximum is recorded at the Observatory in July but at the Peak in August and September. The excess of these readings over the respective mean maxima of air temperature are also exhibited. These figures, although they do not embody any definite measure of solar radiation, are perhaps for want of anything better useful for comparison with other places in the world. At the Observatory they are highest in July and at the Peak in December. The prevalence of fog at the latter station during parts of the year is evidently the cause of the general defect of radiation there, while the excess over the Observatory in December may perhaps prove to be real.
The same table shews the excess of the minimum air temperature above the minimum thermometer placed one inch above the ground. At the Observatory the ground was not turfed till August. The terrestrial radiation during the night reached a maximum in December. In spring and early summer the radiation thermometer at the Peak did not register lower than the temperature of the air, owing no doubt to the fog. But those figures do not exhibit a correct measure of the terrestrial radiation, as little as the figures referring to solar radiation, as the grass minimum gets wet from fog and rain an thus reads lower than the correct radiation temperature.
The same table exhibits the average height in feet to which one must ascend in order to have the mean temperature decreased one degree Fahrenheit. The figures have been computed from the medi temperatures in Table II, whereas in the monthly, weather reports observations at Cape d'Aguilar web! also taken into account. The decrease of temperature with increasing height exhibits an annuel variation. It was a minimum in March, when the lower level of the clouds lay below the Peak, and
a maximum in June.
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