F 12
The mean time clock, Dent No. 39740, which was fitted with an invar pendulum in 1915, has kept a fairly satisfactory rate throughout the year. A discussion of the monthly rates for 1916, using a barometer coefficient of 0'4, gave a temperature coefficient of 0.00421 decrease of losing rate for an increase of 1° (F) of temperature, and this is corroborated by the 1917 rates.
1.
The Brock clock has been used throughout the year for dropping the Time Ball and for driving dials in various parts of the building. In spite of the invar pendulum fitted in 1914, the rate has been erratic at times, after keeping remarkably steady for several days. The clock is corrected daily by the electric regulating apparatus and its daily rate is usually kept below 0.5 by the addition or removal of weights to or from the pendulum.
Since 1916 March 23 an hourly time signal has been sent to the Water Police Station, the General Post Office, and the Cable Company's Office, along the lines used for the telephone or telegraph instruments, by means of apparatus designed by the Government Electrician. An electro-magnet receives a current every hour from the mean time clock and, by means of contacts on the armature, short-circuits these lines for about 0.8 second.
Batteries.-The necessary current for the time service, etc., has been satisfactorily supplied by the accumulator battery, charged as found necessary from the alternating mains of the China Light & Power Co. through a Nodon valve. The charge lasts from 4 to 7 days, according to the state of the atmosphere. A duplicate valve similar to that constructed by Messrs. Jeffries and Evans in 1915, was ordered from the Hongkong & Whampoa Dock Company and brought into use on April 17. The two valves have been used alternately since that date. Occasional troubles have been experienced owing to local impurities in the aluminium electrodes; but the experience of the past year tends to show that these valves have a very high degree of efficiency, if care is taken to keep the electrodes and connections of the valve clean and the precipitation removed about every two months. It also appears that the valves are not large enough. When charging a small battery at 2 ampères the efficiency was considerably higher than when charging the main battery, which requires 4 ampères.
Time Signals by Wireless Telegraphy.-The mast for the wireless time-signal installation was completed by the Taikoo Dock Company in October. It is a steel lattice mast 150 feet high, of triangular section. The installation was not completed by the end of the year, as the wire, etc., for the antennæ, which was ordered in May 1917 was not received till January 1918.
IX. SPECIAL INVESTIGATIONS.
The Wind at Victoria Peak.-The tabulation of the anemograph records at Victoria Peak, Hongkong, is being continued. It is proposed to discuss the results for the years 1914-18 in conjunction with those at the Observatory, Kowloon.
F 12
The mean time clock, Dent No. 39740, which was fitted with an invar pendulum in 1915, has kept a fairly satisfactory rate throughout the year. A discussion of the monthly rates for 1916, using a barometer coefficient of 0'4, gave a temperature coefficient of 00421 decrease of losing rate for an increase of 1° (F) of temperature, and this is corroborated by the 1917 rates.
1.
The Brock clock has been used throughout the year for drop- ping the Time Ball and for driving dials in various parts of the building. In spite of the invar pendulum fitted in 1914, the rate has been erratic at times, after keeping remarkably steady for several days. The clock is corrected daily by the electric regu- lating apparatus and its daily rate is usually kept below 05 by the addition or removal of weights to or from the pendulum.
Since 1916 March 23 an hourly time signal has been sent to the Water Police Station, the General Post Office, and the Cable Company's Office, along the lines used for the telephone or telegraph instruments, by means of apparatus designed by the Government Electrician. An electro-magnet receives a current every hour from the mean time clock and, by means of contacts on the armature, short-circuits these lines for about 0'8 second.
Batteries.-The necessary current for the time service, etc., has been satisfactorily supplied by the accumulator battery, charged as found necessary from the alternating mains of the China Light & Power Co. through a Nodon valve. The charge lasts from 4 to 7 days, according to the state of the atmosphere. A duplicate valve similar to that constructed by Messrs. Jeffries and Evans in 1915, was ordered from the Hongkong & Whampoa Dock Company and brought into use on April 17. The two valves have been used alternately since that date. Occasional troubles have been experienced owing to local impurities in the aluminium electrodes; but the experience of the past year tends to show that these valves have a very high degree of efficiency, if care is taken to keep the electrodes and connections of the valve clean and the precipitation removed about every two months. It also appears that the valves are not large enough. When charging a small battery at 2 ampères the efficiency was considerably higher than when charging the main battery, which requires 4 ampères.
Time Signals by Wireless Telegraphy.-The mast for the wireless time-signal installation was completed by the Taikoo Dock Company in October. It is a steel lattice mast 150 feet high, of triangular section. The installation was not completed by the end of the year, as the wire, etc., for the antennæ, which was ordered in May 1917 was not received till January 1918.
IX. SPECIAL INVESTIGATIONS.
The Wind at Victoria Peak.-The tabulation of the anemo- graph records at Victoria Peak, Hongkong, is being continued. It is proposed to discuss the results for the years 1914-18 in conjunc- tion with those at the Observatory, Kowloon.
No comments yet.
Private notes are available after approval.