[ 9 6 i 
generally erred in defed, they in fome parts erred 
in excels. 
On the 14th of February, 1690, Mr. Flamfteed 
obferved, that a fmall ftar, of the feventh or eighth 
magnitude, whofe place is not determined in the 
Britifh catalogue, and which ftar was named by him 
Infra Ardiurum, preceded Ardurus three feconds in 
time, or 3", 3, when an allowance is made for the 
error of the plane of the inftrument= o' 42", 6, and 
was 26' 30" to the fouth of Ardurus *. By a mean 
of eight obfervations made at Oxford, on and near 
June the 10th, 1767, with the tranfit inftrument, 
and with a refrading telefcope of eight feet, furnifh- 
ed with a micrometer ; the difference of right afcen- 
lion was 1', W',75 of a degree, the ftar following 
Ardurus ; and by a mean of three obfervations, 
the extremes differing only 3"* the fmall ffar was 
2 3' 55", o to the fouth of Ardurus. 
The right afcfenfion of Ardurus and the fmall ftar 
being nearly the fame, the change in declination 
ought to be fo likewife. But, from the obferved 
difference in declination, the right afceniion of the 
two ftars muff vary unequally, though with a very 
fmall difference; Accordingly it appears from com- 
putation (in which the annual preceflion is fuppofed 
— 5o // ,35, the obliquity of the ecliptic at the mid- 
dle of the interval of the time rr 23 0 28' 30", 
and the right afcenfions and declinations of the two 
ftars taken at a mean between the times of obferva- 
tion) that the variation of Ardurus in right afcenfion 
was 3270^,6, and of the fmall ftar 3277^,6 in 
* Th is is the only obfervation of that flar made by Mr. 
Flamfteedc, 
$7,28 
