# Appendix F
REPORT OF THE DIRECTOR
OF THE ROYAL OBSERVATORY, HONG KONG,
FOR THE YEAR 1930.
## 1:-GROUNDS AND BUILDINGS.
The grounds were kept in order by the Botanical and Forestry Department with the assistance of the Observatory coolies.
Magnetic Station at Au Tau.-The daily range of temperature in the magnetograph house is too great for satisfactory registration of magnetic horizontal force and vertical force. Temperature control apparatus to reduce this range has been ordered from England.
Underground Chamber for Seismographs and Clocks.-The range of temperature in the Underground Chamber was 11°.6 (F) in 1930, as against 9°.7 (F) in 1929 and 10°.7 (F) in 1928. The relative humidity was usually above 95% between April 18 and September 2. The absolute range during the year was 46% in 1930, as against 45% in 1929 and 45% in 1928.
In the following table the mean monthly temperature and humidity in the Underground Chamber are compared with the temperature and humidity in the Open Air,