42 
Mr. Pond on the changes in the 
without exception, let us select some striking examples of 
deviation, in particular groups of stars, on which we might 
be satisfied to rest the issue of this question. Of these groups 
I have marked five, in the table of stars arranged according 
to north-polar distance, each of which we will take the pains 
to consider more attentively. 
i. There are six stars in my Catalogue north of y Draconis, 
of which three are found to the north, and three to the south of 
their computed places. These inequalities may appear at first 
sight to be wholly accidental ; but if we pay attention to the 
right ascension, we shall find that the three which appear to 
the northward, are situated in that part of the heavens as to 
right ascension where the southern deviation is the least per- 
ceptible, and that the three which appear to the southward, are 
in that part as to right ascension where the southern deviation 
is the greatest. But of these six stars there are two, a Cassio- 
peiae, and 7 Ursae Majoris, which deserve farther consideration. 
These two stars are within less than one degree of each other 
in polar distance, and consequently pass over the meridian at 
nearly the same altitude. The observations of Bradley on the 
stars north of the zenith are not so numerous as could be 
wished ; but each of the two stars in question was observed by 
him about five times towards the year 17 53 ; that is 60 years 
from the date of my catalogue of 1813. I have carefully 
recomputed the predicted places of these stars, and I find 
x Cassiopeice not less than 1 ",5 to the south of its predicted 
place, and 7 Ursse Majoris half a second to the north. Now 
I am quite at a loss to conceive how this difference in so 
small an arc can arise from error of observation, and I 
can only attribute it to that cause, whatever it may be, which 
