ECLIPSE OF THE SUN.

Dominion, Volume 4, Issue 1023, 12 January 1911, Page 6

ECLIPSE OF THE SUN.

« — SCIENTIFIC EXPEDITION. FROM AUSTRALIA TO FRIENDLY ISLANDS. On April 28 the sun will rise in Sydney almost totally eclipsed, and the eclipse ■will be visible for about an hour and a quarter, that is from about half-past six to a quarter to eight (says the Sydney "Daily Telegraph"). Partial eclipses are not much use to scientists, so a party of observers are .going from Sydney to the Friendly Islands to take photographs of the darkened sun, and find out all they can about it. They are travelling the 2750 miles each way, and will be absent seven weeks, for the sake of 'three minutes in which they will be able to work. Other scientists are making trips of SOOO miles from Great' Britain. America is also' sending Eclipses are mainly useful' nowadays . for ascertaining the nature of the sun's constitution, and by means of the spectroscope finding out -what the sun is' composed of. The inner portion of the sun consists of a mass of incandescent gas, SOO.OOO miles in diameter, under high . pressure. -Around that is the reversing layer, which is made up of metallic gases such as iron, sodium, and lime. Next is tho colour sphere, which is composed mostly of hydrogen aud helium gases, and on the outside of all is the corona, which is a halo of pearly light, extending for at least 3,000,009 miles in every direction. It is this, corona about which scientists hope to gather useful information. Professor Moors, secretary of the eclipse committee of the Association, for. the . Advancement of. Science, who will be of n party,. states that, except'when tho sun is totally eclipsed the corona could not ho seen.. It extended sometime;' as much as .two, ■ three, or more diameters of , the sun. and even when the sun was 'darkened only a part of the corona could be seen. Probably tho rays from it .extended, under favourable circumstances, as far as. the earth. There appeared ,to be a close relation between the corona and the size and number of. the sun spots'. At the forthcoming, eclipse it }?as ps-oocted that the corona would appear in the shape of huge equatorial rays, with shorter ravs from the polos of tho .sun, but when the eclinse occurred at Hobart last May, the photographs taken did not appear to bear-out this<theory. On account of the last celinso beiug obscured bv x clouds the official 1 observers were unable to take'nliotos, arid the pictures secured were taken from other parts of Tasmania by casual observesrs, mostly with, ordinary snapshot cameras. Scientists were anxious" therefore, to see whether the .theory now held would bo borne out, or whether it would have to ho ab?.udoned. • . •• • • Professor Hoors exmamed that periods of sun snots went in cycles of 11-yeax.?. About every eleven years the sun became badly spotted, and the sun: spot period was'then said to be at a maximum. U th~.t time tho sun seemed ,to be in' - a stormy state, and meteorlwnsts woro seeking to ; find out how.this affected tho weather on-the earth. From tho 'maximum neriod the fj>ots on the sun became less in number aud 'size until, the minimum period'was reached, and so the 'maximum and - minimum periods alter".The' earth's atmosphere, said, Professor Moors, absorbs about half tho light energy which reaches it from .the.sun, and the eye only observes a certain amount of tho light'-which penetra.es the,atmcs- . phero But. a camrra looKing contiiuiousiy observer, a' great deal more, 'and by •moans of .the camera it is. hoped to 'ifld out how far the sun's corona ."really, does extend. A total eclipse of the sun lasts oiilv three or four minutes, so that m the" past 20 years only about half an hour altogether lias been available for observation. As many photographs will be taken as time will permit—perhaps 40. The exposure will be from one second to half-.n.-minute.,.:, ■ . Besides Professor Moors, two members .of the Astronomical Society _will ..accom.pany the. expedition from Sydnev, .and j there will also 'be .Mr._B,araccln.,Government Astronomer of .Victoria j.Mr.: Merfield, of the Melbourne' Observatory;'and Dr. Kenny, of Melbourne. Perth- will probably, be represented by the Govern'mmt"Astronomer (Mr. Cook),. and two A deiaide astronomers, are expected to join the partv'.' Tho expedition - will leaVe Svdn-sy by fiTe.' Island' steamer Tofua on ?.Fi»sh '28, and will reach Vavau, in the pMidiv Islands on April 13. Vavau-is about nine and a half mileS long and six ■ami three-ouarters wide. It has d population of about 3000 natives, who grovi many coconuts. ■ '

The' Commonwealth Government lias subscribed : jCoOO : to\vards the -trip, '-'but Professor Jloors says it will: cost everyone who goes . perhaps .£SO 'each as well.