THEIR ARRANGEMENTS AND FORMATION. 3 



tions by the telescope, so as to ascertain the conditions of 

 different parts with respect to the frequency of stars. The re- 

 sult has been a conviction that, as the planets are parts of 

 solar systems, so are solar systems parts of what may be called 

 Astral Systems that is, systems composed of a multitude of 

 stars, bearing a certain relation to each other. The astral 

 system to which we belong, is conceived to be of an oblong, 

 flattish form, with a space wholly or comparatively vacant in 

 the centre, while the extremity in one direction parts into two. 

 The stars are most thickly sown in the outer parts of this vast 

 ring, and these constitute the Milky Way. Our sun is be- 

 lieved to be placed in the southern portion of the ring, near its 

 inner edge, so that we are presented with many more stars, and 

 see the Milky Way much more clearly, in that direction, than 

 towards the north, in which line our eye has to traverse the 

 vacant central space. Nor is this all. A motion of our solar 

 system with respect to the stars, first suggested by Sir Wil- 

 liam Herschel in 1783, has since been verified by the exact 

 calculations of M. Argelander. The sun is proceeding towards 

 a point in the constellation Hercules. It is, therefore, receding 

 from the inner edge of the ring. Motions of this kind, through 

 such vast regions of space, must be long in producing any 

 change sensible to the inhabitants of our planet, and it is not 

 easy to grasp their general character ; but grounds have never- 

 theless been found for supposing that not only our sun, but 

 the other suns of the system, pursue a wavy course round the 

 ring, from west to east, crossing and recrossing the middle of the 

 annular circle. " Some stars will depart more, others less, from 

 either side of the circumference of equilibrium, according to the 

 places in which they are situated, and according to the direction 

 and the velocity with which they are put in motion. Our sun 

 is probably one of those which depart furthest from it, and 

 descend furthest into the empty space within the ring." 1 

 According to this view, a time may come when we shall be 

 much more in the thick of the stars of our astral system than 

 we are now, and have, of course, much more brilliant nocturnal 

 skies ; but it may be countless ages before the eyes which are 

 to see this added resplendence shall exist. 



The evidence of the existence of other astral systems is much 

 more decided than might be expected, when we consider that 



1 Professor Mossotti, London, Edinburgh, and Dublin Philosophical 

 Magazine, 1843. 



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