F 14
The clock tripped two seconds on September 15. It was cleaned and the contact springs re-adjusted on September 24.
The Dent Mean Time clock (No. 39740) was used throughout the year for dropping the Time Ball, maintaining the electric time service in the Observatory, and sending hourly signals to the Railway, the Post Office, the Telephone Co., and the Eastern Extension Telegraph Co. The clock is corrected daily before 10 a.m. by the electric regulating apparatus, and its daily rate kept below 0.5 sec. by the addition or removal of weights from the pendulum.
Chronometer Dent No. 40917 is on loan to the Cape d'Aguilar Wireless Station, and chronometer Dent No. 39946 to the Peak Signal Station. Chronometer Woolf No. 5232 was forwarded for safekeeping to the Observatory by the Hon. Colonial Treasurer in August, 1920, and has been kept wound and rated since.
Batteries, Power Supply, &c.-The necessary current for the Time Service has been supplied by accumulator batteries, charged as found necessary from the alternating mains of the China Light and Power Co., Ld., by a rotary converter. Two batteries of 10 Hart cells of the S. G. 9-plate pattern were set up in May to replace the old Tudor Battery, all the cells of which had become unserviceable except two. These were used for the filament of the valve of the wireless receiving set. A battery of 30 Pritchett cells was set up at the same time to supply high tension current to the valve.
Since the re-wiring mentioned last year, and the acquisition of sufficient battery power, the internal Time Service has been extremely satisfactory.
The occasional trouble with the Time Ball, arising from earth leakage or want of adjustment of the releasing trigger, also appears to have been overcome. There has been no failure since September 27.
IX.-UPPER AIR RESEARCH.
When on leave of absence in England the Director was requested to confer with the Air Ministry with a view to advising the Hong-kong Government what it was necessary to do on the meteorological side to assist aviation in the Colony.
The Director visited the upper air research stations at Benson and South Farnborough, and also conferred with the Director of the London Meteorological Office and the Superintendent of Instruments several times.
Facilities for obtaining the necessary information were courteously accorded by Sir Napier Shaw and the Superintendents of the above Departments, to whom the thanks of this government are due.