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, as in the case of the sidereal standard clock, gives a temperature coefficient of 0421, decrease of losing rate for an increase of 1° (F) of temperature.
The Brock clock has been used throughout the year for dropping the Time Ball and for driving dials in various parts of the building, except from October 27 to November 7, when Dent No. 39740 was used for this purpose. 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.
Further experiments with the electric sidereal clock indicated that the best working conditions are with an angle of impulse β — 12′ and γ+74', giving an arc of about 160'. The clock is now out of commission, pending the construction of an underground room for all the clocks. It will then be required for driving a dial in the transit room.
In the month of October the minute dials missed occasionally. The fault was traced to the Edison-Lalande cells which operate the minute relay circuit. Dry cells were substituted and the dials have since worked without failure.
Since 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 Edison-Lalande cells which were purchased for use alternatively with the accumulator on some circuits, have proved a failure. In some cells the zincs have been eaten through at the level of the potash, and others have become exhausted, though called upon to do but very little work.
The accumulators have given satisfaction throughout the year. Additions to the sulphuric acid have been made occasionally, as required. The ammonium phosphate requires filtration after about two months' work.
Time Signals by Wireless Telegraphy.—A tuner and detector, with a high resistance telephone, were received in the month of March. They were tested by the Port Wireless Officer and found satisfactory; but the Audion amplifier, purchased by the Crown Agents from Messrs. A.W. Gamage, was found useless, so was returned to the makers.
The Marconi Company have been asked to quote for the installation of antennae and mast for the receipt of wireless time-signals in accordance with a specification prepared by the Port Wireless Officer.
F 12
The mean time clock, Dent No. 39740, which was fitted with an invar pendulum in 1915, has kept a fairly satisfactory rate through- out the year.
A discussion of the monthly rates for 1916, using a barometer coefficient of 0'4, as in the case of the sidereal standard clock, gives a temperature coefficient of 00421, decrease of losing rate for an increase of 1° (F) of temperature.
The Brock clock has been used throughout the year for drop- ping the Time Ball and for driving dials in various parts of the build- ing, except from October 27 to November 7, when Dent No. 39740 was used for this purpose. 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.
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Further experiments with the electric sidereal clock indicated that the best working conditions are with an angle of impulse ẞ — 12′ and y+74', giving an arc of about 160'. The clock is now out of commission, pending the construction of an underground room for all the clocks. It will then be required for driving a dial in the transit room.
In the month of October the minute dials missed occasionally. The fault was traced to the Edison-Lalande cells which operate the minute relay circuit. Dry cells were substituted and the dials have since worked without failure.
Since March 23 an hourly time signal has been sent to the Water Police Station, the General Post Office, and the Cable Com- pany'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 Edison-Lalande cells which were purchased for use alternatively with the accumulator on some circuits, have proved a failure. In some cells the zincs have been eaten through at the level of the potash, and others have become exhausted, though called upon to do but very little work.
The accumulators have given satisfaction throughout the year. Additions to the sulphuric acid have been made occasionally, as required. The ammonium phosphate requires filtration after about two months' work.
Time Signals by Wireless Telegraphy.-A tuner and detector, with a high resistance telephone, were received in the month of March. They were tested by the Port Wireless Officer and found satisfactory; but the Audion amplifier, purchased by the Crown Agents from Messrs. A.W. Gamage, was found useless, so was re- turned to the makers.
The Marconi Company have been asked to quote for the install- ation of antennae and mast for the receipt of wireless time-signals in accordance with a specification prepared by the Port Wireless Officer.
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