672565-1884-Report-on-the-Mean-Cloudiness-of-Hongkong- — Page 1

SUPPLEMENT

To the HONGKONG GOVERNMENT GAZETTE of 1st March, 1884.

WVERNMENT NOTIFICATION.-No. 73.

The follow.ag sport from the Government Astronomer is published for general information.

By Command,

Colonial Secretary's Office, Hongkong, 1st March, 1884.

W. H. MARSH,

Colonial Secretary.

II. K. O.

No. 80.

HONGKONG OBSERVATORY, 24th February, 1884.

SIR, I have the honour to submit the accompanying account of the average degree of Cloudiness of Hongkong. It shows that the atmosphere here is particularly clear during the autumn, while the spring is rather dull. Just the reverse of this obtains in land, where clear weather is common only in spring. The importance of this circumstance cannot be over-estimated from an astronomical point of view. It is a fact well known to practical astronomers that the part of the sky which is visible during the spring months in the evening in the United Kingd has been especially investigated, while the autumn sky is still comparatively less known. It now appears that Hongkong is most favourably situated for observing during the autumn. So that not only can phenomena be watched here at an hour when they are invisible in Englaud, owing to the difference in Longitude, but that even abstracting from Southern Constellations, the part of the Northern sky which it is most difficul: to observe in England can be particularly well explored from this Colony.

I have the honour to be,

Sir,

Your most obedient Servant,

The Honourable The COLONIAL SECRETARY,

&c.,

&ling

ge.

W. DOBERCK, Government Astronomer.

On the Mean Cloudiness of Hongkong.

The amount of sky covered by clouds has been roughly noted for several years at Cape d'Aguilar at Victoria Peak at different equidistant hours during the day, but no records were kept during thi 1. The following results are therefore not free from the influence of the diurnal variation of the

ount of clouds, but they exhibit nevertheless clearly the annual variation.

The mean amount of sky covered by clouds, expressed in percentage of the whole sky, during !! different months of the years 1880-1884 inclusive, is exhibited in Table I:-