282 SOLAR MOTION. 



Investigation It M'il] give aclditional force to the arguments I hare used 

 motion o?Thc ^^^ ^^^^ admission of far distant centres of attraction, as 

 ««n. well as projectile motions in the stars that are connected 



with them, when we take notice that, independent of the 

 solar motion, and setting that entirely aside, the action 

 of these causes will be equally required to explain thet 

 acknowledged proper motions of the stars. For if th« 

 sun be at rest, then Arcturns must actually change its 

 place more than 2" a year, and consequently this and 

 many other stars, which are well known to change their 

 situation, must be supposed to have projectile motions, 

 and to be subject to the attraction of far distant centres. 



Determination of the Quantity of the Solar Motion, 



If I am not mistaken, it will now be allowed that no 

 '^ objection can arise against any solar velocity we may fix 

 upon, for want of a cause that may be assigned to act 

 upon the sun, and many stars, so as to account for their 

 motions, and similar tendency toward a certain part of 

 the heavens ; we may consequently proceed in examining 

 whether the quantity that has been assumed for calculat- 

 ing the contents of the Xlth Table, will sufliciently come 

 up to the conditions we have adopted for directing our 

 determination. 



In Fig. 6 WQ have the velocities of the 3G stars deline- 

 ated, and by examining the last column of the Table 

 from which they are taken, we find that the parallactic 

 elFects arising from the proposed solar motion require the 

 velocity of ] 8 stars to exceed that of the sun, and exactly 

 the same number to be inferior to it ; so far then tha 

 rank which has been assigned to the solar motion is a 

 perfect medium among the sidereal velocities. 



If we examine in the next place how this motion will 

 agree with a mean rate deduced from the velocities in 

 the above mentioned column, we find a 36th part of their 

 sum to be 1196550. A solar motion, therefore, which 

 agrees with this mean rate will differ from one assigned by 

 the middle rank no more than 'j079538 ; and, on ac- 

 count of the smallness of this quantity, the calculations 

 required to lessen it, by some little increase of the solar 



motion, 



