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Appendix A.
THE CLIMATE OF HONGKONG INVESTIGATED FROM
FIVE YEARS' OBSERVATIONS.
Palin
The Colony of Hongkong is situated within the tropics, but the winter is cool, its mean temperature being about 60°, whereas the mean temperature of the summer rises a little above 80°. There is a large and well-marked variation of climate, but it is very hot in the sun all the year round. trees, rice and sugar canes grow here. Pomelos, oranges and pine-apples are among the most extensively cultivated crops opposite on the mainland, but do not thrive in the Colony on account of unsuitability of soil. About forty species of palms from all parts of the world thrive in the Botanic Gardens, and from temperate regions many coniferous trees thrive side by side with tropical palms. The conifers are from Japan, Queensland, the Cape, and India (Himalaya). The Norfolk Island Pine is quite at home here. Banian trees are common, and bamboos attain to great size. Vines do not come to perfection as the winter temperature is not low enough to harden the wood.
In spring, between the two monsoons, bronchial catarrh and pneumonia are prevalent. Measles, mumps and simple continued fevers are very common,
In summer; the dampness of the air is excessive. Europeans suffer much from prickly heat and similar diseases, produced in consequence of the heat and dampness. The Chinese are also very subject to diseases of the skin, especially the different varieties of Tinea. Malarial fevers and diarrhoea are the worst hot weather diseases, the former chiefly of an intermittent type in summer. They are worst in August and September, when the Colony is under the influence of the high-pressure areas preceding and lying to the north of typhoons. In these areas the wind is light and the air descending, so that it is stifling, dusty, and probably full of bacteria. Want of sleep during such weather tends to produce anomia from loss of appetite and thereby lays the foundation for many diseases such as diseases of the brain.
In autumn, the dampness of the air decreases, and the temperature falls often rather suddenly when the NE monsoon sets in. This causes affections of the chest and catarrhs, but Europeans enjoy almost an immunity from phthisis while to the Eurasians this is an ever present scourge. Malarial fevers assume more frequently the remittent and bilious remittent type. Beri-beri is frequent among the natives, but cholera is never more than a minor evil in Hongkong.
In winter, dysentery-the dreaded scourge of the Pacific-occurs. This is the worst disease of the Chinese coast, and often leads to abscess of the liver. Small-pox is endemic and occasionally epidemic. Typhoid fever is very rare, but typho-malarial fevers are more common during the end of the winter and also in spring along the southern coast of China and Annam.
The most unhealthy places are situated in ravines between the hills, near marshy land or paddy fields. In such places malaria is deadly. Between one and two thousand feet up on the hills the air is pure and fever less common and of a milder type, which is as a rule easily cured by quinine. It is more agreeable to live in the upper regions although the air is frequently saturated with moisture.
Table I. exhibits the mean height of the barometer reduced to freezing temperature of water, but not to sea level, with its annual and daily variation. For January-March inclusive, the diurnal variation is obtained from the last 4 years' (1885-1888 inclusive) observations only, but the annual means depend upon 5 years' observations as the monthly means for January-March, 1884, were obtained from readings made at 10a. and 4p. The entries for March and April at the Peak are the means of 4 years only. The data are of great practical importance as the diurnal variation although lessened in damp. weather is not much influenced by storms. During the approach of a typhoon it is necessary to correct the readings for daily variation in order to know how much the mercury is falling.
Table II. exhibits the mean temperature. The means for 1884 were obtained from thermometers in Stevenson's screen, the readings being reduced to true air temperature. The hourly variation of temperature depends upon 4 years' observations only. The highest temperature occurs about 2p., and the lowest between 6a. and 7a., in winter and about 5a. in summer.
Tables III. and IV, exhibit the mean humidity and its variations. The latter depend upon 4 years only as far as the three first months are concerned. The relative values vary inversely to the temperature while the actual amount of vapour is greatest a few hours after sunset, and least shortly after sunrise. In winter, there is nearly as much vapour at the Peak as at the Observatory, but in summer there is less.
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Table V. exhibits the average amount of bright sunshine. It is great in November, and small in February! The daily maximum occurs about nooù, and there is more sunshine in the afternoon, than in the forenoon. The entries for January and February are the means of 4 years only. The percentages are the means of the 4 last years only.