228 THE YICTORIAN NATUEALIST. [Vol. rSIII. 



able to take full advantage of the great gift that Nature 

 had given in her splendid forests. He himself would 

 be pleased to hear from the teachers if they thought he 

 could be of use in identifving specimens or giving in- 

 formation. 



ASTROXO^ITCAL DEMONSTRATIONS. 



By R. J. A. Barnard, M.A., Lecturer in Mathematics, 

 and Natural PhilosofJiy, Qtieen''s and Ormond 

 Colleges, Melbourne University. 



Air. Barnard pointed out first some of the more im- 

 portant constellations and brighter stars ; and explained 

 that the stars were, from early times, classed according 

 to their brightness in six classes or magnitudes. In 

 modern times, this classification has been made more 

 accurate by dividing the magnitudes up so that we now 

 speak of a star as being of magnitude 2.4 or 5.6, or any- 

 thing else of the kind, so that there is a regular gradation 

 from the first magnitude to the sixth, the latter being the 

 faintest visible to the ordinary naked eye. A tenth of a 

 magnitude is the smallest difference that one can generally 

 be sure of in comparing two stars. 



Starting from near the Southern Cross, Alfha Centauri, 

 the brighter of the two " Pointers," and the nearest 

 star to the earth, was seen, with the small telescope lent 

 to the camp, to consist of two separate stars, which, in 

 reality, revolve round one another in eighty years. The 

 fainter of these two is very similar to the sun in con- 

 stitution, mass, and brilliancy, and probably also in 

 size. Their distance apart averages only a little more 

 than the distance of Uranus from the sun. Among 

 other objects observed were clusters of stars in the Milkv 

 Way in Argo, especiallv the great combination of star 

 cluster and nebula surrounding Eta Carinse (better known 

 probablv as Eta Argus). This star is itself remarkable 

 for having been, between 1840 and 1850, equal in bright- 

 ness to Sirius, the brightest star in the sky. At present, 

 it is invisible to the naked eye. Another remarkable 

 nebula, that in Orion, was also well seen in this tele- 

 scope. Recent photographs show that this nebula really 

 extends over the whole of the constellation of Orion. 



One or two of the brighter variable stars were also 

 pointed out, especially I Carinse, whose variations in 

 brightness are very easv for a beginner to observe, either 

 Avith the naked eye or with the help of a field glass. To 

 make such observations, it is onlv necessarv to have a 



