432 PEOPER MOTIONS OF THE STARS. [SECT, xxxvn. 



it hatf left, and that there would be a regularity in these 

 apparent motions which would hereafter be detected. Since 

 Sir William Herschel's time the proper motions of the stars 

 have been determined with much greater accuracy, and 

 many have been added to the list by comparing the ancient 

 and modern tables of their places; his views have been 

 established by four of the greatest astronomers of the age, 

 MM. Lundahles, Argelander, Otto Struve, and Peters, who 

 have clearly proved the motion of the sun from that of the 

 stars in the northern hemisphere, and Mr. Galloway has 

 come to the same conclusion from the motions of the stars 

 in the southern hemisphere. The result is, that the sun, 

 accompanied by all his attendant planets, is moving at the 

 rate of 42-2424 miles or over a space nearly equal to his 

 own diameter in the course of a day, and that the motion is 

 directed towards a point in a line joining the two stars 

 p, and TT Herculis at a quarter of the apparent distance of 

 these two stars, reckoning from TT Herculis. Should the sun 

 be moving in a nearly circular orbit, the centre of motion 

 would be in the plane passing through the sun perpen- 

 dicular to the direction of his motion. The constellations 

 through which that great circle would pass are Pisces, 

 Australis, Pegasus, Andromeda, Perseus, &c. M. Argelander 

 is of opinion that the sun's orbit is nearly in the plane of 

 the Milky Way, and, therefore, that its centre must probably 

 be in Perseus, while M. Madler places it in the Pleiades, 

 and nearly in the direction of the star Alcyone of that 

 group; but the data are too uncertain to admit of any 

 absolute conclusion as to the sun's orbit. Though the stars 

 in every region of the sky tend towards a point in Hercules, 

 it is not yet known whether their motions are uniform or 

 variable, whether the sun's motion be gradually changing, 

 and whether the stars form different independent systems, 

 each having its own centre of attraction, or if all obey one 

 powerful controlling force which pervades the whole uni- 

 verse. 



