$88 Capt. Kater's experiments for determining the variation 
At Unst, the following series of observations for the zenith 
distance of the sun's upper limb was made under the most 
favourable circumstances. The calculation of the latitude of 
this, as well as of the other stations, is given at length, to 
afford the opportunity of any examination that may be thought 
desirable. 
Unst. 23d July, 1818. Barometer 30 inches, thermometer 6i°. Time of 
apparent noon o h .6 m .2 s ,3. The chronometer too fast 47 s , 9. Time by the chro- 
nometer at apparent noon o\6 m .50 $ ,2. 
Chronometer. 
Level. 
Time from 
Noon. 
N. v. Sines. 
h. m s. 
m. s. 
23 - 49-39 
+ 
4 
- 5 
17.U 
2809 
23.51.46 
+ 
5 
— 2 
15. 4 
2160 
23.54.11 
+ 
3 
- 3 
12.39 
1523 
23.56.36 
+ 
2 
- 3 
10.14 
0997 
23.59.H 
+ 
4 
— 1 
7-39 
°557 
0. 1. 2 
+ 
4 
— 0 
5.48 
0320 
0. 3.29 
+ 
5 
+ 2 
3.21 
0107 
0. 6. 5 
+ 
3 
— 1 
0.45 
0005 
0. 9.41 
+ 
3 
— 1 
2.5 ! 
0077 
0.1 1.23 
+ 
4 
+ 3 
4-33 
0197 
0.13.26 
+ 
4 
+ 
6.36 
0415 
0.14.59 
+ 
4 
+ 3 
8. 9 
0632 
Mean 
+ 45 
— 5 
0817 
( + 45 - 5 ). • 
X 2,4— + 48,0 correct, for the level. 
« / // 
Lat. 60.45.26 cosine - 9.6888746 
Dec. 20.10.57 cosine - 9.9724798 
Alt. 49.26.33 cos. co. ar. - 0.1869458 
Log. sine 1 co. ar. - - 5.3144251 
Log. 817(4-4) 6.9122221 
Readings, &c. G 's U. L. 
Corr. — 1 i 8 // ,83 log. 2.0749474 
First Vernier 
0 / // 
- 123.58.30,00 
Second 
58. 0,00 
Third 
57.55,00 
Fourth 
- 58.10,00 
Mean 
- 123.58. 8,70 
4- 360. 0. 0 
Level 
- -f- 0.2^8 
Index 
- -f 0. 1 8 
12)483.59.14,7° 
Observed Z. D. 
40.19.56,22 
Refract. 
+ 0 48,43 
Paral. 
- — 0. 5,67 
Semidiam. 
+ 15.46,50 
Correct. 
— 1-58,83 
Change of Dec. 
4- 0.2,16 
(Z-Z') 
+ 0,34 
True Z. D. 
40.34 29,05 
Dec. 
- 4- 20.10.57,36 
Lat. of Unst. 
- 60.45 26,41 
