F 6
# VI-MAGNETIC OBSERVATIONS
12. The Magnetic Station at Au Tau has been kept in action throughout the year, and the results of the observations are now in the press.
# VII-TIME SERVICE
13. Clocks Cottingham and Mercer 507 (Sidereal) and Leroy 1350 were in use throughout the year. The necessary astronomical observations for the determination of the error of the former were obtained each evening (weather permitting) by the local staff. Observations of the radio time signals emitted by Nauen have been made daily whenever possible during the year and utilised for Clock regulation.
14. Time Signals were given throughout the year by radio from 9.55 a.m. to 10 a.m. each morning and 8.55 p.m. to 9 p.m. each evening. Dots of about 0.1 second duration were transmitted at each second except for periods marking the minutes and half minutes. The evening programme was duplicated by three white lights (vertical) on the radio mast, the lights being extinguished each second in accordance with the radio programme.
Hourly signals were sent to the General Post Office, Radio Studio, Railway, the associated Telegraph Companies and the Telephone Company.
The errors of the time signals have been published monthly in the Government Gazette.
# XI-MISCELLANEOUS
15. Aviation service. -A synoptic chart of the Far East, on which is also all available information concerning upper winds, is prepared and exhibited in the aerodrome, and a senior officer is available for consultation by departing pilots. An hourly weather report is broadcast daily, usually from 0600 to 1600 Hong Kong Standard Time, and is communicated in Q code directly to incoming planes. A route forecast is also furnished to the pilots of outgoing planes.
16. Seismographs.-The seismographs have been kept in good order throughout the year, 372 earthquakes were recorded, compared with 398 in 1937. The seismographs have been forwarded to the International Seismological Committee, Oxford.
17. Upper Air Research.-Observations of 607 pilot balloons were made during the year.
Details of the flights will be included in Meteorological Results for 1938.
Observations of upper air temperature, taken during aeroplane flights, have been supplied to the Observatory by the personnel of the Far East Flying Training School Ltd., and of the Civil Airport, to whom acknowledgements are due. These observations were commenced on September 8th, and from that date until the end of the year 55 meteorological flights were undertaken. Flights usually extended to a height of 10,000 feet.
The results were plotted in the form of entropy diagrams at the Observatory; they have proved of material assistance in forecasting cloud formation, and it is hoped that they will add considerably to our knowledge of the structure of the atmosphere.
18. Lithography.-Lithographic work for other departments was undertaken as follows:
Colonial Secretariat Map of Hong Kong 1,000 Medical Department Map 450 Medical Department Chart 500