1822.] Apparent Place of } Urse Minoris for 1822. 129 
ArTIcLE VI. 
On the Apparent Right Ascension of  Urse Minoris as a Verifi- 
cation of the Meridian Position of a Transit Instrument. By 
James South, FRS. &c. 
(To the Editor of the Annals of Philosophy.) 
SIR, Blackman-street, July 24, 1822. 
WuateEver tends to promote accuracy in the practical part 
of astronomical science, 1s a fit object of encouragement ; and 
if more than others there be observations in which accuracy 
is important, it is those of right ascension; for accordingly 
as these are well or 2// determined, will the various observa- 
tions of which they form the basis, prove beneficial or tnju- 
rious. Fortunately the instrument employed for this purpose is- 
so simple in its construction, that with a proper degree of cau- 
tion on the part of its employer, it affords results little lable to 
error ;* still, however, no opportunity of examining not only its 
adjustments, but alsoits position relatively to the meridian,should 
pass unembraced ; and for the latter purpose, frequent obser- 
vations, not of a tottering mark which may be here to-day and 
there to-morrow, but of high and low stars whose relative right 
ascensions are well settled, or of the superior and inferior 
transits of circumpolar stars, are absolutely indispensable: if the 
former be recurred to, na stars are so proper as those of Dr. 
Maskelyne’s Catalogue; the mode, however, is a dependent 
one; the latter, therefore, where the instruments will allow of its 
use, being not liable to this objection, is generally preferred ; 
and when it is remembered that the instrument which passes 
through the zenith and bisects one or other of these stars, at 
intervals of 12 hours + the corresponding correction in right 
ascension, must move in the plane of the meridian, it is surely to 
be regretted that the daily corrections of the principal ones, 
within 15° of the pole, have not been computed. Under these 
circumstances the Ephemeris of the pole star, published by 
Mr. Baily in the Phil. Mag. of June, 1820, 1 have found 
extremely useful; and with the idea that a similar table of 
3 Urse Minoris would be little less acceptable to the practical 
astronomer, | avail myself of this opportunity of giving it publi- 
city. The star is visible in the day-time, culminates about six 
hours after the pole star, within a few seconds of a Lyre, 
within a few minutes of Sirius, and travels over the wires of the 
instrument nearly in half the time that the pole star does. Like 
the table of polaris, the accompanying is the produce of foreign 
industry, and the original, and, I believe, the only copy in this 
country, is in the possession of the Astronomical Society of 
London. J. SouTu. 
* As enjoying this valuable property, I by no means include those transit instru- 
ments which have stuck upon one end of their axes a circle, accurately to show (as is 
pretended) north polar distances. ‘These specimens of wisdom are, I believe, but few 
im number, and it is to be hoped they will remain go. 
New Series, you. 1V. K 
