north polar distances of the principal fixed stars. 67 
“ one another in right ascension, and not far from either of 
“ the colures, I shall set down the result of the comparison 
“ of a few that differ so little in declination, that I could 
“ determine the quantity of that difference with great cer- 
“ tainty.” He then states, that the mean difference of decli- 
nation was 10' 28", 1, on March 27, (old stile) 1727. This, 
reduced to January 1, 1727, new stile, is 10' 38", 4. 
The declinations of these stars in 1755, reduced from Dr. 
Bradley’s observations with the Greenwich quadrant, by 
Mr. Bessel,* are 
a Cassiopeae 55 0 1 1' 2 3", 7 
y Ursae Maj. 55 3 24 ,4 
Difference 7 59 ,3 
Dr. Maskelyne observed these stars at Schehallien, 1774. 
The observations^ of the zenith sector, reduced to January 1, 
1774, by the usual equations, give 
Z. D. 
a. Cassiop. 
Z. D. y 
Ursae Maj. 
Oct. 2 
i° 22' 45",5 
Oct. 14 
1° 43' 22",2 
3 
43 >5 
! 5 
2 5 >4 
5 
45 >7 
18 
2 3 >4 
2 4 
46 ,4 
22 
22 ,3 
Mean 
1 22 45 >3 
Mean 
1 43 2 3 >3 
1 22 45 >3 
Diff. decl. 20 38 ,0 
Diff. ref. 4- o ,4 
20 38 ,4 
M. Piazzi,j Palermo. 
Declination, 1800. 
y Ursae . 54 0 48' 23" ,0 
«■ Cassiop. 55 26 17 ,6 
Diff. 37 54 ,6 
* Astron. Fund. pp. 140, 208. t Phil. Trans. Vol. 65. 
t M - Piazzi’s Great Catalogue, “ Panormi, 1814.” 
