?.68 Mr. hekschel on the proper Motion 
having the folar fvftem in its center. Afliime the direction AB 
from a point fomewhere not far from the 77th degree of light 
afcenfion to its oppohte 257th degree, and fuppofe the fun to 
move in that direction from S towards B ; then will that one 
1 not ion anfwer that of all the ftars together : for if the fun po- 
litico be true, Arcturus, Regulus, Pollux, Procyon, Caller, 
and Sirius, Ihould appear to decreale in right afcenlion, while 
a. Aquila?, on the contrary, ihould appear to increafe. More- 
over, fuppofe the fun to afeend at the lame time in the fame 
direction towards Come point in the northern hemiiphere, for 
instance, towards the conllellation of Hercules ; then will alio 
the obferved change of declination of Sirius and Arcturus be 
refolved into the fjngle motion of the folar lyflem. I am well 
aware of the many yet remaining difficulties, fuch as the cor- 
refpondence of the exact quantity of each liar’s obferved proper 
motion with the quantity that will be affigned to it by % this 
hypothelis ; hut we ought to remember, that the very different 
and ftill unknown relative dillances of the hxed liars mull, 
for a good while yet, leave 11s in the dark about the particular 
-and ft rift application of the theory ; and that any deviation from 
it may eafdy be accounted for by the Hill unknown real proper 
motion of the ftars : for if the folar fyftem have the motion I 
aferibe to it, then what aftronomers have already obferved con- 
cerning the change of place of the ftars, and have called their 
proper motion, will become only an apparent motion ; and it 
will Hill he left to future obfervations to point out, by the 
deviations from. the general law which the ftars will follow in 
thole apparent motions, what may he their real proper motions 
as well as relative diftances. But left I fhould be cenfured for 
•admitting fo new and capital a ..motion upon too flight a foun- 
6 dation, 
