170 Dr. Herschei/s Method of observing the 
n is marked 4m ; d 6.5 m, % and e 4.5m, c and 72 5m ; there- 
fore 7T should be larger than all the former ; but it is less. 
| is marked 4m ; but there are eleven stars, namely, c b 54 
A d x e c 72 27 48 69, all marked in various manners less than 
that star, yet they all exceed it in magnitude. 
Not to proceed any farther with particulars, we ought to 
account for this by allowing that Flamsteed did not compare 
the stars to each other, but referred each of them separately 
to its own imaginary standard of magnitude. This is the real 
source of all such contradictions, which therefore cannot be 
charged to our author. As we should, however, take it for 
granted, that the magnitudes were affixed to the stars with as 
much care as the nature of ajn unsettled standard would allow, 
a short inquiry into the extent of the confidence we may place 
upon the method of magnitudes will be of considerable use. 
We have observed that in this method the brightness of 
stars is referred to unsettled standards ; but admitting that a 
pretty general though coarse idea may be formed of these 
magnitudes, it may be granted that a mistake of a whole order 
in the first class cannot be supposed. The difference between 
a star of the first and second magnitude is so palpable that it 
excludes all suspicion of taking one for the other. 
When subdivisions are introduced, the case becomes doubt- 
ful. 1.2m may easily pass for 2.1m. But though these two 
notations should not be sufficiently clear to be distinguished 
from each other, yet I am inclined to believe that the former 
may be precise enough to point out a difference from 2m, and 
the latter from 2.3m. 
With the next, order of stars the difference is much less 
striking; but yet 2m will convey an idea which may be pretty 
