Transit of Venus.

Star (Christchurch), Issue 4880, 21 December 1883, Page 4

Transit of Venus.

[Pbb Pbbbb Asbooiation.] WELLPvGTON, Deo. 20. lhe final observations in connection with the transit of Venui were concluded at the Mount Oook Observatory last night. When Oolonfl lupmao, of the Venus expedition, waa here he was prevented by unfavourable weather and hia ahort stay from personally oonduoiing the observations neoeißary to determine tho precise longitude of New Zealand. These were accordingly entrusted to the Sur-veyor-General, who undertook, to prooure the required data, and under Mr M'Kerrow's supervision tne work has since been oarried on, Dr Leaion auperintending the necessary electrical arrangements. The actual observations have been made by Mr 0. W. Adams, first geodesical surveyor, Mr T. L. Barker, assistant, and the telegraphio arrangements were oonduoted by Mr J. Gell. On the otber side, at Bydnoy, the observations wore made by Mr H. 0. Bussell, the Government Astronomer, Mr H. H. Lenahan first assistant; and Mr J. S. Shepley, Superintendent of the Oable Oompany, superintended the electrical arrangements, his Oompany having granted the free use of the oable for the purpose of these important observations, to determine the exaot time at each end of the base line, and so fix the exaot longitude of New Zealand. The method adopted for ascertaining the preoise sidereal time, was by simultaneous observations of tbe transit of a number of fundamental " clock" stars, and to prevent the ohance of error, these observations had to be repeated on four nights, the signals boing transmitted by telegraph, direot from the Sydney to the Mount Oook observatory. All the lines being oonneoted on such a long oircuit, the electrio ourrent wos necessarily weak, and ooasequently tbe signals had to be received, not by the ordinary instruments, but by Thomson's reflecting galvanometers. As it was neoessary for Buocossful observations that the weather should be absolutely clear, both at Sydney and here, and that the eleotrical conditions should be favourable, it has oooupied five weeks to obtain four satis* faotory nights' work. On eaoh of these four nights 108 observations were made at each end, and the results duly reoorded by the electrio ourrent. These carefully taken 432 aignala will, it ia believed, render error almost impossible, and, as Mr 0. W. Adams recently visited both Melbourne and Sydney for the puroose of asoertainiug the amount of personal error existing between all the observers employed, it is believed that the observations whioh were olosed at Mount Oook last 1 night will determine the longitude of New Zealand, as compared with Greenwioh, to

within a ohain. The results will be forwarded to Oolonel Tuptnan, and are expeoted to prove highly valuable, both in regard to the Transit of Venue observation and in navigation generaUy.