172 Transactions. — Miscellaneous. 



intensely heated than it is now. All the elements of which it is composed 

 were there uncombined. Hydrogen, the gas of the smallest density, 

 ordinarily extended furthest from the centre of the globe, and this hydrogen, 

 its outer envelope, was nearly always near the confines of the normally cold 

 regions of space. Thus it would have a somewhat lower temperature than 

 the rest of the sphere, and hence well-marked hydrogen lines would appear 

 in its spectrum at this period. Comparatively small quantities of other 

 elements, however, would frequently be erupted from the interior portions 

 of the sphere, and would reach what may be called the surface. The 

 presence of these would cause the appearance of numerous fine lines in the 

 spectrum. As eternity went on, if I may use the expression, the star 

 radiated a large portion of its heat into space, the elements began to combine 

 chemically to a certain extent, large volumes of hydrogen ceased to exist as 

 such, through combining with oxygen and forming water-vapour, of which 

 the outer star envelope would now consist. In place of the hydrogen hues 

 of the white star therefore, we now find the aqueous vapour spectrum — " the 

 atmospheric lines " as they are called. The result of the combination of 

 the oxygen and the hydrogen would, of course, be a great decrease in the 

 volume of the outer envelope. This would probably bring the lines of 

 sodium, magnesium, iron, and calcium into greater prominence, and we 

 should have the spectrum which y Crucis now presents. Between the two 

 conditions described there would be an intermediate one. Through such a 

 stage our Sun may possibly be passing now. It may be, in short, that 

 our Bun was once a Sirius, is now a Procyon, and will by-and-by be a y 

 Crucis. This is a mere hypothesis, of course, though it appears to account 

 pretty fahiy for some of the phenomena of the stars. In fact, I give it 

 merely as a suggestion, feeling that it is as little entitled to carry weight 

 with it as an hypothesis, founded on observed phenomena and not at vari- 

 ance with known facts, can be. 



y CentaurL—'R. A. 12hrs. 84min. 21-46secs. Decl. 58° 14' 43-24".— This 

 is a very fine close pair of stars, each component being of the fourth magni- 

 tude, and purely white. In his " Eesults of Observations at the Cape 

 of Good Hope," Sir John Herschel gives the position-angle as 354-3°, the 

 epoch being 1835-89, while the distance is stated to be f". To this estimate 

 of distance Herschel attaches no value. For the year 1878-93 the angle of 

 position is 6-6°, or 186-6°, and the distance 2-2' 



/3 Crucis. — This fine white star has a distinct deep blood-red companion, 

 the position angle being 260^^° and the distance (1879)-208". It seems to 

 me that the small star varies in size from about the eleventh to nearly the 

 eighth magnitude. It would be well if the smaU star could be watched, so 

 that its period and the amount of its variation in brightness might be 

 accurately ascertained. 



