^4. 



But it 13 not ftt 

 that all che real 

 motion fhouid 

 be afcribed to 



Capella j 



but the apex 

 mull be taken 

 io as to leave the 

 real motions as 

 ioiall as poffible. 



apparent mo- 

 tions of fix 

 blight ftars 



MOTION OF THE SV!fk 



ihitd ftar is accounted for by retaining the fame apex o^ th^ 

 folar motion which explained the apparent motions of the 

 other two, yet a great degree of real motion has been affigned 

 to Capella, of which Arflurus and Sirius have been altogether 

 deprived ; which fliews that the apex of folar motion muft be 

 fo fixed as lo be equally favourable to every ftar proper for 

 direfting our choice. Hence a problem arifes, for difcovering 

 a point whofe fituation among three given apices (hall be 

 fuch as if the fun's motion be directed towards it, there may 

 be taken away the greateft poflible quantity of proper motion 

 from the three given ftars. The intricacy of this problem is, 

 that by a change of the diftance of the apex from any one of 

 the ftars, its parallaftic motion, which is^s the fine of that 

 diftance, will be affeded ; fo that it is not merely the altera* 

 tion of the angle of diredlion which is concerned. From the 

 folution of this problem, a much more complex one would 

 arife, as three ftars would certaialy not be fufficient to dire6l 

 the prefent endeavour to find the beft fituation of an vape^ fij»C 

 the folar motion. 



It was before fhewn that the brighteft flarsare the moft pro- 

 per for demenftrating the effeft of parallax, and that in fearcbing 

 after the direflion of the folar motion, the aim ihould be to 

 reduce the proper motions of the ftars to their loweft quantities. 

 The fix principal ftars, whofe interfering arches have been 

 given, when their proper motions in right afcenfion and polar 

 diftance are brought into one direflion, will have the following 

 apparent motions : 



«at>ul3tej. 





Names of the 

 Stars. 



bireftlon of the apparent Motions. 



Quantities of 

 the apparent 

 Motions, per 

 Year 





SirfUs, , 



Arfturus, 



Capeila, 



Lyra, 



Aldebaran, 



Procyon, 



68° 49' 40.7" South-preceding. 



55 29 42.0 Ditto. 



71 35 22.4 South-following. 



56 20 57.3 North-following. 

 76 29 37.3 South-following. 

 50 2 24.5 South-preceding. 



I. 11528" 



2.08718 



0.46374 



0.32435 



0.12341 



1.23941 





Sum of the apparent Motions, 



5.35337 



In 



