284 SOLAR MOTION. 



Investigation made, by way of objection to the solar motion I hav« 

 motion of^the ^^^^'^ upon. If the quantity of this motion is to be as- 

 »un. signed by the mean rank of sidereal velocities, it may be 



asked, will not the addition of every star, whose proper 

 motion shall be ascertained, destroy that middle rank, 

 which has been«^stablished ? To this I shall answer, that 

 future observations may certainly afford us more exten- 

 sive information on the subject, and even show that the 

 solar motion should not exactly hold that middle rank, 

 which from various motives ive have been induced to 

 -assign to it; but at present it appears, that according to 

 the doctrine of chances, a middle rank among the sidereal 

 velocities must be the fairest choice, and will remain so, 

 unless, what is now a secondary consideration, should 

 hereafter become of more importance than the first. 

 That this should happen is not impossible, when a gene- 

 ral knowledge of the proper motions of all the stars of 

 the 1st, 2d, and 3d magnitudes can be obtained ; but then 

 the method of calculation that has been traced out in this 

 and the former Paper, is so perfectly applicable to any 

 new lights observation may throw upon the subject, that 

 a more precise and unobjectionable solar motion can be 

 ascertained by it with great facility. Hitherto we find 

 that a mean rank agrees sufficiently with the phenomena 

 that were to be explained : the apparent velocities of Arc- 

 turus and Aldebaran, without a solar motion for in- 

 stance, were to each other, in the IXth Table, as 208 to 

 12; our present solaj- motion has shown, that when the 

 deception arising from its parallactic effect is removed by 

 calculation, these velocities are to each other only as 179 

 to 85, or as 2 to 1, And though Arcturus still remains 

 a star that moves with great velocity, yet in the Xlth 

 Table we have 4 or 5 stars with nearly as much motion ; 

 and 4 with more. 



Our solar motion also removes the deception by which 

 the motion of a star of the consequence of cc Orionis is so 

 concealed as hardly to shov/ any velocity; whereas by 

 computation we find that it really moves at a rate which 

 is fully equal to the motion of the sun. 



I must now observe, that the result of calculations 

 founded upon facts, such as we must admit the proper 



motions 



