late Professor of Practical Astronomy in Glasgow. 295 



minion incomparably wider in extent, and that the order and 

 stability, even of a universe, and of every individual system com- 

 prehended in it, might depend upon periodical motion round 

 some grand centre of general gravitation. This conception, be- 

 sides appearing to them warranted by every view they could take 

 of the nature of gravity, seemed moreover to receive some sup- 

 port from the discoveries which, since the time of the great HA- 

 LEY, have been made of what has been called the " Proper mo- 

 tions of the fixed stars," and particularly from the opinion enter- 

 tained by that excellent astronomer Dr MASKELYNE, " That, 

 probably, all the stars are continually changing their places 

 by some slow and peculiar motions throughout the mundane 

 space." 



Soon after this view had arisen, out of the familiar conversa- 

 tion above mentioned, it was published in a very short anony- 

 mous tract, entitled, " Thoughts on general Gravitation, and 

 Views thence arising as to the state of the Universe." The 

 chief inducement to so early a publication, was the hope of draw- 

 ing immediate attention to so interesting a point, which might 

 possibly lead to the discovery of some way by which the matter 

 might be brought to the test of observation. 



It is quite obvious, that the foregoing suggestions necessari- 

 ly imply a motion of the solar system, as one of that immense 

 host, which, for what we yet know, may be subjected to the laws 

 of periodical revolution. Accordingly, it early occurred, that, 

 perhaps the most advantageous way of advancing in this investi- 

 gation, might be to try to find out, if possible, symptoms of such 

 a law as affecting that system to which we ourselves belong. 



It sometimes struck him, when looking over the progress of 

 philosophical discovery, that many things of high moment appear 

 to have lain long wrapped up in embryo, by our not employing 

 ourselves more frequently in what may be called " a direct search" 

 and in filling up with more attention and boldness the list of de- 

 VOL. x. P. ii. p p 



