24-2 On the Motion of the Sun and Soiar System. 



of direction, which is concerned. However, it will not be 

 necessary to enter into a solution of the problem ; tor 

 it n)ust l>e very evident that a much more complex One 

 w oidd immediately succeed it, since three stars would cer- 

 tainly not be sufficient to direct us in our present endea- 

 vour to find the best situation of an apex for the solar mo- 

 tion ; I shall therefore now leave these stars, and the apices- 

 pointed out bv then), in order to proceed to a more general 

 view of the subject. 



We have alreadv seen that tb.c brightest stars are most 

 proper for showing the efll-d, of parallax, and that in our 

 search after the direction of the solar motion, our aim must 

 be to reduce the proper motions of the star* to their lovt'esl 

 quantities. The six principal stars, whose intersecting, 

 arches have been given, when their proper motions in right 

 ascension and polar distance are brought into one direction, 

 will have the apparent motions contained in the foUowina; 

 Table. 



Table H. 



Names of the [ Dirsction of the apparent 

 Stars. Motions. 



■^inus - ' 

 \rcturus ■ 

 CapeUa - 

 Lyra 



Aldebaran 

 Procyon - 



G8° 49' 40,7" S. preceding 

 .■)5 129 42,0 S. preceding 

 71 35 2'J,4 S. tollovving 

 5Q 20 57,3 N. following 

 7ii 29 37,3 S. following 

 50 2 24,5 S. preceding 



Slim of the appaxent motions 5,3')337" 



Quantitie"! of the apparent 



Motions. 



1,1152S" per vear 



2,08718 



0,4G374 



0,32435 



0,12341 



1,239-il 



We must now recur to what has been said, when the con- 

 r.truclion of the triangle expressing the three motions of a 

 star, that is not at rest, was explained ; and, as we are to 

 ilnd out a solar motion which will require the least real 

 moti^tn in our six. stars, an attention to this triangle will be 

 of coriHiJcrable use ; for when the line p a, Fig. 1, which 

 rf'picstnts the real motion, is brought into the situation 

 rri a, Tvherc it is perpendicular to s p, the real motion 

 wliieh is required will then be a minimum. It also follows, 

 from the construction of the same triangle, that if by the 

 choice of an a[ex for the solar motion we can lessen the 

 angle made at i- bv the lines s' p and s a, we shall lessen 

 the quantitv of .real motion required to bring the star from 

 the paralUiclic line s p m to the obsei-v'ed position a. 



It h::? alreariv been sliown, in the case of Sirius and Arc- 



ttirus, that whun U\u stars onlv arc given, the line s p may 



7 ' be 



