t 256 ] 
third magnitude, and his light, at a medium diftance, 
upon this hypothecs, would be, I apprehend, about 
a 50th part of that of Sirius. And therefore, accord- 
ing to the reafoning above, we fhould then find it an 
equal chance, that the parallax of one half of thefe 
350 ftars would not be lefs than about 8 //r/ 4. ; and 
there would be the fame chance, that the parallax of 
no one amongft them would be more than between 
50 ;// and about 1 " . 
In the former fuppofition of 1000 ftars •, the 
apparent magnitude of the Sun, when removed to 
the medium diftance; &c. it feems not improbable, 
that the biggeft ftar in the fyftem may perhaps exceed 
the Sun, in the proportion of about 1000 to 1 ; and 
in the latter fuppofition of 350 ftars, &c. that it may 
perhaps exceed the Sun, in the proportion of about 
120 to 1. 
In whatever proportion the diameter of the Sun is 
greater or lefs than the medium we have taken for it 
in the fuppofitions above, in the fame proportion will 
the parallaxes be increafed or diminifhed j and in the 
inverfe triplicate of that proportion muft their mag- 
nitudes be diminifhed or increafed. 
Let us now examine the circumftances of the Plei- 
ades ; and, affuming the refpe&ive diftances of the 
ftars, compofing that fyftem, from each other to be, 
at a medium, equal to thofe of our own, let us fee 
what will be the confequences of this fuppofition. 
Now, if the Pleiades do not extend farther in the 
dire&ion of aline drawn between the Earth and them, 
than in a direction at right angles to that line (which, 
from their compofing a fyftem, we have a right to 
fuppofc they do not) we can hardly allow the mean 
diftance 
