[ 2 52 ] 
to be in reality a fyftem of ftars, the probability is at 
leaft, I fuppofe, an hundred to one, that no one 
amongft them, of thofe vifible to the naked eye, 
belongs to the fame fyftem with the Sun ; but that 
thefe are only fuch ftars, as are greater than the red. 
The exad quantity of this probability depends upon 
the number of ftars, vifible to the naked eye, belong- 
ing to this fyftem ; the proportion, that the fpace 
occupied by the Pleiades bears to the whole heavens ; 
and laftly, how far the fituation of any one of the 
Pleiades falls in with the general analogy of the ftars 
compofing this fyftem, if any fuch general analogy 
fhould appear. 
As the nebulas, and fmaller conftellations, compofed 
of a great number of ftars, within a fmall diftance 
from one another, belong probably to other fyftems ; 
fo thofe, which being placed at greater didances from 
each other compofe the larger conftellations, and fuch 
as have few or no fmaller ftars near them, when 
examined with telefcopes, belong probably to our 
ewn fyftem. Moft of the ftars of the firft and 
fecond magnitude have this criterion to didinguifh 
them as belonging to the fame fyftem with the Sun, 
befides feveral other circumftances, fuch as their 
greater, brightnefs ; the proper motions *, that have 
1 The apparent change of fituation, that has been obferved 
amongft a few of the ftars, is a ftrong circumftance in favour of 
thofe ftars being fome of the neareft to us. This apparent change 
of fituation may be owing either to the real motion of the ftars 
themfelves, or to that of the Sun, or partly to the one, and partly 
to the other.. As far as it is owing to the latter (which it is by 
no means improbable may in fome meafurc be the cafe) it may be 
confidered as a kind of fecular parallax, which, if the annual 
parallax of a few of the ftars fhould fome time or other be d if— 
covered, and the quantity and direction of the Sun’s motion 
6, becfl. 
