THEIR ARRANGEMENTS AND FORMATION. 7 



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. Sir William Herschel, so early 

 as 1783, detected a motion in our solar system with re- 

 spect to the stars, and announced that it was tending to- 

 wards the star A, in the constellation Hercules. This has 

 been generally verified by recent and more exact calcu- 

 lations,* which fix on a point in Hercules, near the star 

 143 of the 17th hour, according to Piozzi's catalogue, as 

 that towards which our sun is proceeding. It is there- 

 fore, receding from the inner edge of the ring. Motions 

 of this kind, through such vast regions of space, must be 

 long in producing any changes sensible to the inhabitants 

 of our planet, and it is not easy to grasp their general 

 character ; but grounds have nevertheless 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 emp ty space 

 within the ring."f 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 ot 

 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 

 besides oar own is much more decided than might be ex- 

 pected, when we consider that the nearest of them must 

 needs be placed at a mighty interval beyond our own. 

 The eld&f Herschel, directing his wonderful tube towards 

 the sidu ot our system, where stars are planted most 

 rarely, ti d raising the powers of the instrument to the 



* Made by M Argelander, late director of the Observatory 

 at Abo. 



t Proieraor Mossotti, on the Constitution of the Sidereal System, 

 5>f which the Sun forms a part .—London, Edinburgh, and Dublin 

 Philosophical Magazine, February, 1843. 



