Colonial Time-Ball Observatory.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 36, 1903, Page 517

Colonial Time-Ball Observatory. Mr. Thomas King, the officer in charge, reports as follows:— The clocks have kept satisfactory rates throughout the year, and the instruments are in good order. There are no

points calling for special remark in connection with the regular time service, the duties of which have had attention as heretofore. Towards the end of 1903 I had pleasure in co-operating with Mr. Otto J. Klotz, Government Astronomer of Canada, in the New Zealand section of the very important work which has been undertaken by the Dominion Government in the shape of a determination of the longitudes of a number of fundamental points on the route of the Pacific cable. At the instance of the Department of the Interior, Ottawa, Mr. Klotz carried a chain of longitude-work from Greenwich to the Pacific coast of Canada by means of the telegraph - line, and thence to Australia and New Zealand over the new Pacific cable. The station in New Zealand the position of which he sought to fix in the coarse of this survey was Doubtless Bay, in the northern part of the Provincial District of Auckland, a temporary observatory being erected by him there near the spot at which the cable comes ashore. It was necessary for his purpose that a meridian distance should be ascertained between his observing-station and some spot in New Zealand the longitude of which had already been well determined, and Wellington Observatory was naturally selected as best fulfilling this requirement. By direction of the Hon. the Postmaster-General, special telegraphic communication was established between the observatories at Wellington and Doubtless Bay. Very full sets of transit observations were simultaneously taken on suitable nights by Mr. Klotz at Doubtless Bay and by myself at Wellington, the stars selected being chosen with a view both to the accurate determination of our respective local sidereal times and to the elimination of our instrumental errors. The nights on which these observations were secured were those of the 6th, 7th, 10th, 11th, 12th, 17th, and 18th December, the work beginning soon after dark and ending after midnight. On several of these evenings we succeeded in observing twenty stars per night, of which sixteen were ordinary “clock stars” and four were circumpolar stars for the determination of the azimuth and collimation errors of the transit instruments. The Wellington and Doubtless Bay clocks were automatically compared on the same nights by means of the telegraph and chronograph, the clocks being placed on the main line for several minutes at a time so as to record at once on both chronographs. Thus the seconds of the Wellington sidereal clock were simultaneously pricked off on the Wellington and on the Doubtless Bay chronographs, and the seconds of the Doubtless Bay sidereal clock were in like manner recorded on the Doubtless Bay and Wellington chronographs. By sending the signals in both directions any error due to wave and armature time on the

telegraph-line was got rid of. After the completion of the work Mr. Klotz came to Wellington and conducted with me at the Observatory a series of observations for the purpose of ascertaining the difference between our respective personal equations. He also thoroughly satisfied, himself as to the adjustments of the transit instrument, with the view of taking into account its several “constants of correction”; and he similarly tested the striding-level. Details of my transit-observations and level-readings, with the original chronograph records and my full “scalings” of the same, and also a report on the work, were handed to Mr. Klotz in January last, and will in due course be incorporated in his general report on the survey. Copies of these documents are attached hereto; but presumably they need not be printed, as the Canadian report, which will cover the whole ground, will be forwarded to the colony by Mr. Klotz as soon as it is published. In view of the fact that the use of the siphon recorder in cable-work has greatly increased the accuracy attainable in transmitting time-signals for longitude purposes, it will be of interest to see how Mr. Klotz's final results compare with those obtained in 1886, when a very elaborate series of determinations was effected by cable from Greenwich in the opposite direction (namely, eastwards), across India to Madras, and from that point by intermediate stations to Australia. On New Year's eve, at the request of the United States Government, a set of signals was received from the United States Naval Observatory, Washington, for the purpose of ascertaining the minimum time in which a signal could be repeated over a long distance from station to station by cable. Owing to hasty preparation the test was only partially successful; but the last signal sent would appear to have reached Wellington Observatory from Washington in about four seconds. It was transmitted from Washington to Greenwich in 1·3s., and to Sydney in about 3·5s. Rear-Admiral Chester, Superintendent of the United States Naval Observatory, in a letter addressed to Mr. W. Gray, Secretary of the Post and Telegraph Department, expresses the opinion that, considering the short notice given, the cable and telegraph operators did very well on this occasion. The experiment was an extremely interesting one, and there is a possibility that Admiral Chester may propose a repetition of it at some convenient future time. March, 1904.