SOLAE MOTION. 273 



real direction ; but should a star, such as Aldcbaran, investigation 



move toward the apex with less velocity than tlie paral- ^^ ^}^^ proper 

 , . , . . .11 . r motion of the 



lactic motion which opposes it, there will arise a change gun. 



of direction, and the star will be s«eu moving toward the 



opposite part of the heavens. 



Trial of the Method to obtain the Qaantitj/ of the Solar 

 Motion hif its Ra?ifc among the sidereal Velocities. 



According to the conditions that have been explained, 

 a calculation may be made with a view of equalizing th$ 

 velocities of the sun and the star a Orionis ; and the re. 

 suit of it will show that the proposed equality will be 

 obtained when the solar motion is 1 ",266230. It will 

 moreover be found that so small an increase of this mo- 

 tion as 0",01 would give us 19 stars with less, and 17 with 

 more velocity than that which the calculation assigns to 

 the sun ; this consequently fixes one of the limits to which 

 the solar motion ought not to come up, if we intend it 

 should hold a middle rank among the sidereal velocities. 



On the other hand, by a similar calculation of the velo- 

 cities of the star Pollux and the sun, it appears that a 

 solar motion of 0,967734 will make them iqual ; and 

 that a diminution of this motion not exceeding 0",0l 

 would give us 1 9 stars moving at a greater rate than the 

 sun, and only l/falling short of its velocity. This con- 

 sequently fixes the other limit to which the solar motion 

 ought not to be depressed. And thus it appears by this 

 method, that the quantity we are desirous of ascertain* 

 ing, is confined within very narrow bounds, and that by 

 fixing upon a mean of the two Hmits, we may have the 

 rank of the solar motion true to less than 0"5l5. 



Calculations for investigating the Consequences arising 

 from any proposed Quantitif of Solar Motion^ and for 

 delineating them hij proper Figures, 



Before we can justly examine the real motions of sfars 

 which it will be necessary to admit in consequence of a 

 given solar motion, it will be convenient to have them 

 represented in two figures that we may see their arrange- 



VoL. XV,— J)ec. 1806. O Q ment 



