130 IN STARRY REALMS. 



are both separated from our system. This we know 

 because we often see the stars actually revolving one 

 around the other, not, it is true, with any very rapid 

 motion, in the ordinary acceptation of the word. One of 

 the stars may require many years to complete a revolution 

 around the other, but the fact that such revolution has 

 been noticed is sufficient in the cases where it occurs to 

 prove the connection existing between these stars. We 

 must also, of course, remember that these stars are suns of 

 stupendous magnitude, and from a view of our own system, 

 in which the great planets take many years to complete 

 one of their mighty journeys around the central orb, it is 

 not in the least to be wondered at that the periods of 

 revolution of these double stars should demand no less 

 intervals of time. 



Many of these double stars are objects of extreme tele- 

 scopic beauty ; sometimes they offer to our admiration a 

 delightful contrast of colours ; perhaps one will be topaz 

 colour and the other bluish, or on rare occasions a pair of 

 emerald gems will be seen with an invisible band of mutual 

 connection. Sometimes triple stars are found, in which 

 three stars are obviously in alliance; but multiple stars 

 of greater complexity are comparatively rare ; and so 

 marvellous a spectacle as Theta Orionis, in which no 

 fewer than six stars are obviously an allied group, is 

 almost unique. It is not a little remarkable that we 

 find the most exquisite multiple star which the sky 

 can show, beautifully framed or set in the centre of 

 the grandest of the nebulae. Of course it might conceiv- 

 ably happen that the apparent concourse of these objects 

 was fortuitous. The actual phenomenon could be accounted 



