THE TRANSIT OF VENUS.

Evening Star, Issue 3110, 6 February 1873, Page 3

THE TRANSIT OF VENUS.

The necessity of observing the transit of the planet Venus over the sun in 1882, from la station in a high southern latitude—nearer [the pole, in fact, than 72deg. is already be[ginning to excite discussion and action among astronomers and geographers. The Astronomer Royal opened the subject in a [paper read before the Astronomical Society ithree months ago, and it has been taken up 'by Commander Davis (a member of Sir J. ! Ross’s memorable expedition of 1839-43), [and discussed at a meeting of the Geographical Society on th: 22n I of February. Un [the accurate observation of the time of the planet’s ingress on the sun’s disc, and egress from it, at stations as wide (apart as possible on the surface of the [earth, depends the accuracy of the astroxoImer’s calculation of our distance from the [sun; and the choice of stations, of course, is limited to those parts of the earth where the sun is sufficiently above the horizon at tic hours of occurrence of phenomenon (between 2h. Srain. and Sh. 2min Greenwich mean solar time), and to areas of land having a climate likely to ensure clear skies for the observation. Two transits of the planet take place in a century, the two occurring at an interval of eight years. The first of these now approaching is on December Bth, 1874, and the sec nd on December Gth, 1882 In the transit of 1874, the position of the planet and sun is such that the method of observing it from two widely distant stations, so as to secure the widest difference of parallax, cannot be carried out, owing to the required stations being in mid-ocean ; but in 1882 it happens that the points suitable for the observation, at either side of the ea,rth, are on land ; one being in the northern part of > orth America, and the other on the shores of the south polar continent. The enormous difficulty of approaching this land of perpetual ice. and snow, and the little that is known of it, give rise to doubts in the mind of the Astronomer Royal, whether the observations, so ardently desired by all men of science, will be carried out. One of the positions suggested by him is Sabrina Land, a tract of the polir continent discovered by Balleny, in 1839, and lying due south of Western Australia. But our knowledge of this portion of the land, and of Terre Adelie, a little further cast, discovered by Dumont d’Urville, is of the most shadowy nature. They were not visited by Ross, and Commander Davis believes the coast there to tend east and west, backed by a range of high lands which would intercept the view of the sun, so little elevated above the horizon at the time of the transit, from observers on the shores. Another desirable station is Possession Bland, muefi farther south, on which Ross’s expedition landed. This high latitude could not be readied from Van D’eman’s Land or New Zealand (one of which must be the starting point) in time to erect the observatory the same summer, so that the party of savans must ba landed the previous summer, and pa- a a winter in these desolate regions. The islands of the coast abound in penguins, but the whole region lies almost beyond the zone of vegetable life, a few scanty lichens alone covering the rocks laid bare by the brief summer thaw. Such au expedition, of course, must be a Government undertaking, and whether it is to became a reality or not depends on the expressed desire of the British public so noble an enterprise be carried out.