224 GENERAL MOVEMENT OF THE STARS. 



The sum of M. Midler's calculations gives for 



80 stars, 1st to 2d magnitude, a mean secular movement proper of 25.09 



200 stars, 3d magnitude, a mean secular movement proper of 17.10 



348 stars, 4th magnitude, a mean secular movement proper of 14. 18 



690 stars, 5th magnitude, a mean secular movement proper of 11. 09 



994 stars, 6th magnitude, a mean secular movement proper of 9.05 



921 stars, 7th magnitude, a mean secular movement proper of 8. 65 



Although, according to this table, the most brilliant stars are those 

 which in the mean have the greatest proper movement, yet the 

 author, in comparing the strongest of those movements in each order 

 of magnitude or apparent brilliancy, and adopting the opinion that the 

 stars of considerable proper movement ought to be in general nearer 

 the sun than the others, concludes that among the stars nearest us 

 those of the least brilliancy appear, absolutely speaking, more nu- 

 merous than those which are more brilliant. In effect, if alpha of 

 the Centaur, Arcturus, Procvon and Sirius have, respectively, a proper 

 annual movement of 3". 67, 2".26; 1".33, and 1".25: on the other hand, 

 Rigel, (the 4th star in order of brilliancy according to Sir John Her- 

 schel,) a of Cygnus and /9 of Perseus have scarcely any proper move- 

 ment at all, while fi of Cassiopeia, the 40th of Eridanus, the 61st of 

 Cygnus, and the two stars named after Argelander, which are of 5th 

 to 7th magnitude only, have proper annual movements of from 4 to 7 

 seconds. It should be also remarked that of 52 stars of the 2d mag- 

 nitude observed by Bradley the mean value of their annual proper 

 movements, as reported by Msedler, page 192 of volume 11 of his 

 Researches, is but 0". 138; while of 150 stars of the 3d magnitude it 

 is 0". 173. Thus, contrary to the ideas adopted by W. Struve, in his 

 Etudes Stellaires, the degree of brightness appears to M. Maxller to be 

 a bad indicator of the relative distance of the stars. 



We have already seen that, admitting that all the stars move around 

 a common centre, without any preponderant mass, and according to 

 the Newtonian law of attraction, the velocities will be very nearly 

 proportional to the distances from that centre; the more uniform the 

 distribution of masses the less will the form of the described orbits 

 vary from the circle. From the central point C, wdiich is in repose, 

 the proper movements of the near as of the remote stars would be 

 equal; but from another point, S, situated at a certain distance from 

 C, the stars nearest to S will appear to move more quickly. M. 

 M;edler is disposed to admit that our sun is situated at about half the 

 interval between the central point and the exterior limits of the space 

 comprised by the stars with which he is engaged; but those stars 

 form not a millionth part of the whole of the visible fixed stars, with- 

 out even taking account of the Milky Way. 



The author commences his new researches with the determination 

 of the movement of the sun and its direction. In this view he sub- 

 divides the stars whose proper movements he has determined into 

 three classes, viz: 



1. Those, to the number of 227, Avhose proper secular movement 

 is greatest, and amounts to a mean of 55". 4. 



