north polar distances oj the principal fixed stars. 61 
few remarks relative to one circumstance, that Mr. Bessel 
relies on a good deal, as proving the exactness of his refrac- 
tions, viz. that they give the obliquity of the ecliptic at the 
Winter and Summer solstices the same. Whereas other 
Tables of refraction give the obliquity in Winter less than in 
Summer. 
We have lately commenced here to observe the zenith 
distance of the sun every day at noon, on which it can be 
seen. 
I had formerly been unwilling to observe the sun with the 
circle, except at the solstices, as I considered the heat likely 
to derange the instrument for my observations relative to 
parallax. 
The Dublin circle, in one respect, is well adapted for ob- 
serving the sun. By observing a few minutes before and 
after noon, four observations give me the zenith distance of 
the centre, independently of the semi-diameter, or correction 
for collimation. 
Observations on eighty-seven days have been obtained du- 
ring the last year. The manner in which I have used them, 
is, I believe, somewhat new. With the declination in the 
Nautical Almanac, and the meridional zenith distance de- 
duced from the observation, I obtain the latitude of the Ob- 
servatory. I assume, that the declination in the Nautical 
Almanac is only erroneous by an error in the longitude (L) 
of the sun, and obliquity of the ecliptic (O). Then, for 
each day, I have the lat. = Z. D. observed + decli. + md L 
+ n dO -\-p dk. From the nature of the Solar Tables it may 
be assumed, and the assumption is exact enough for my en- 
