on the local arrangement of the celestial bodies in space . 307 
The number of the stars of the 4th magnitude is by the 
catalogue 454, and by the order of distances 386. 
Before I proceed, it may be proper to remark, that, by 
these four classifications of the stars into magnitudes, it ap- 
pears already, that, on account of the great difference in the 
lustre of the brightest stars, many of them have been put 
back into the second class ; and that the same visible excess 
of light has also occasioned many of the stars of the next 
degree of brightness to be put into the third class ; but the 
principle of the visibility of the difference in brightness would 
have less influence with the gradually diminishing lustre of 
the stars, so that the number of those of the third magnitude 
would come nearly up to those of the third distance. And 
as the difference in the light of small stars is less visible than 
in the large ones, we find that the catalogue has admitted a 
greater number of stars of the 4th magnitude than the 4th 
order of distances points out ; this may, however, be owing 
to taking in the stars that were thrown back from the pre- 
ceding orders ; and a remarkable coincidence of numbers 
seems to confirm this account of the arrangement of the stars 
into magnitudes. For the total number of the catalogued 
stars of the 1st, 2d, 3d, and 4th magnitudes, with the addition 
of the sun, is 735; and the number contained in the whole 
sphere of the 4th distance is 729. 
Now the distinguishable difference of brightness becoming 
gradually less as the stars are smaller, the effect of the prin- 
ciple of classification will be, as indeed we find it in the 5th, 
6th, and 7th classes, that fainter stars must be admitted into 
them than the order of distances points out. 
