Diftance, Magnitude, Sc. of the Fixed Stars, ec. 43 
the fquare root of 247.009, and the fquare root of 247.008, 
which amounts, as above, to fomewhat lefs than one 494.000li 
part of the whole quantity. 
18. The fame effects would likewife take place, according 
to article 11, if the femi-diameters were different from thofe 
mentioned in the two laft articles, provided the denfity was 
greater or lefS in the duplicate ratio of thofe femi-diameters in- 
verfely. | 
19. The better to illuftrate this matter, it may not be amifs 
to take a particular example. Let us fuppofe then, that it 
fhould appear from obfervations made upon fome one of thofe 
double ftars above alluded to, that one of the two performed 
its revolution round the other in 64 years, and that the central 
one was of the fame denfity with the fun, which it muft be, 
if its apparent diameter, when feen from the other body, was 
the fame as the apparent diameter of the fun would be if feen 
from a planet revolving round him in the fame period: let us 
further fuppofe, that the velocity of the light of the central 
body was found to be lefs than that of the fun; or other ftars 
whofe magnitude was not fufficient to affect it fenfibly, in the 
proportion of rg to 26. In this cafe theti, according to arti- 
cle 17, the {quare root of 247.009 SS muift be to the fquare root 
ef the difference between 247.009 SS and aaSS as 20 to 19. 
But the fquares of 20 and 19 being 406 and 361, the quantity 
247.009 SS muft therefore be to the difference between this 
quantity and aaSS in the fame proportion, that is as 247.cog to 
222.925,623 and aaSS muft confequently be equal to 24.083, 
33 SS, whofe, fquare root 155,2S nearly, or, in round num- 
bers, 195 times the diameter of the fun, will be the diameter 
of the.central ftar fought. : Me ~ 
G 2 : 20. Ags 
