TRANSIT OF VENUS.

New Zealand Times, Volume XXIX, Issue 4281, 9 December 1874, Page 2

TRANSIT OF VENUS.

Thislong- looked forward to, and most interesting" event in tlie' history of the stars, 1 takes place to-day, as calculated by the astronomers. TJnfor-' tunntely it is greatly to he’ apprehended that 1 the elements will not he propitious, -unless we are favored this afternoon with one of those sudden changes for which the climate of New Zealand, and of Wellington especially, -is remarkable. ■ A clouded - sky all day yesterday would have made observation impossible-had the transit been likely to occur - on : the Bth in place of the 9th. Rain was falling heavily at a late hour last ■ night-; the barometer was falling ratherthan otherwise at a late hour in the ‘Middle Island; and at ■ daylight (this morning the sky was still overcast- and nnpropitious. We hope most fervently that before the hour for which the astronomers will wait and watch -with so much hope and fear, the clouds will' have sufficiently cleared 'away to afford good observations. We have on previous occasions so fully described the preparations made by the English, American, French, and German parties of observation;'as well as by the local obser-vers, that it is unnecessary to repeat them here. The following information, however, as to what has been and-will' be done in Wellington, was supplied in the course of yesterday:— At 9.30 a.m. Dr. Hector will exchange 1 time with Major Palmer, by telegraph, a complete telegraphic system having been constructed under the direction of ,Mr. Smith, of the Telegraph office, - working admirably. Then, the exact identity of time being established, the corps of observers lake their positions, and get everything in readiness for the : beginning of the event. Dr. Hector will observe with the fine 4in. equatorial belonging to the Wellington Observatory, which is massively fixed in a tent at one corner of the enclosure ; Mr. W. F. Parsons observing with the excellent 6in. reflector constructed by, himself, in another tent in the opposite corner. "Mr. Gore will be in charge of the astronomical clock, and will call out each second, which will be recorded by two chronographs, and' also taken down direct by an ■ assistant, on an ingenious’ plan suggested by himself. Mr. Bothamley will be with Dr, Hector, aiid record each iuci-, clout as dictated by the latter, who also, as also Mr. Parsons, will be provided with, an,, electrical apparatus, which by pressing a knob will cause the chronograph to note doivn the exact instant.of each occurrence ..with the. minutest, accuracy.. - At Ih. Ifimim- 18sec. (all - the times, are approximate New Zealand mean) the first external contact of the planet with -the- edge' of the sun’s.disc .will take place, a small indentation appearing in the latter. The planet will advance and gradually appear as a round dark spot. It is the moment of last internal contact at ingress (and conversely that of first internal contact at egress-—-the the’more important of the two) which is the supreme iustapj; - to be noted. It has several distinct phases. , First, the planet ns it recedes from the edge becomes pear-shaped, or

rather assumes the form of a peg-top, the point being towards the sun’s edge. At last, only a small black line appears to connect the two. Suddenly this breaks, which is one of the great incidents, the exact instant of whose occurrence is to be noted. Then the portion of the sun between its edge and the planet becomes _ brown and filmy, suddenly changing to a line of intensely bright white light ; tins is another moment to be noted, and then this disappears, and the planet is fairly on the sun. This last internal contact at ingress will be at Ih. 44m. SOsec. Venus then will be visible on the sun’s face until sh. 18m. 42sec. p.m., and when the first internal contact at egx*ess will occur, a converse repetition of the phenomena already described will be visible Ist, the line of intense light ; 2nd, the brown film ; 3rd, the black line ; 4th,. the pear shape ; sth, the protrusion of the planet over the edge ; and finally, her recession until only, a small indentation in the edge of the sun’s disc remains, which in its turn will disappear at sh. 48m. 30sec., and the transit will be over. Archdeacon Stock will observe the event with his fine telescope from the adjoining cemetery, the time being fixed by chronometers carefully compared. He kindly has undertaken to allow visitors to witness the event through his telescope after two and before five o’clock, between the two critical hours. At other times no one must approach. 'When it is mentioned that the whole of the phenomena which it is so important . to note, will occupy only seven seconds, the extreme necessity for complete absence of interruption at once will be perceived.