in the length of the pendulum vibrating seconds. 439 
Observations for the error of the Chronometer. 
Unst, ISIS, 23d July, P. M. O’s U. L. 
Chronometer. 
Level. 
Readings, &c. 
h. m s. 
4.21 24,5 
4.24.29,5 
4.26.46,0 
• 4.28. 1,5 
+ 7 
+ 5 
+ 10 
+ 9 
— 3 
— 5 
+ 4 
+ o 
° / // 
First Vernier - “ 230-32.15 
Second - 5 
Third - 5 
Fourth - - 10 
Mean - . 4.25.10 4 
True time . 4.24.23,3 
+ 31 
— 4 
Mean - - 239-32. 8,7 
Level - - + 32,4 
Index + 18,0 
Chron. fast - - 47 ^ 
4)239-32.59,1 
( + 31—4) " // 
Observed Z. D. - 59-53.14,8 
Ref. and Parall. - + 1.32,3 
Semidiam. - + 15.46,4 
2 " X -D — +32,4 
True Z D. - - 60.10.33,5 
Unst, 23rd July, P. M. O’s U. L. 
Chronometer. 
Level. 
Readings, &c. 
h. in. s. 
First Vernier 
O / // 
4.3 1 .55 
+ 6 
— 
1 
- 243.58.10 
4.33.16 
+ 4 
— 
2 
Second 
58. 0 
435.32,5 
+ 9 
+ 
4 
Third 
57.50 
4.37. 0,5 
+ 5 
+ 
0 
Fourth 
58.15 
Mean 
True time 
- 4.34.26,0 
4.33.37,9 
+ 24 
+ 
1 
Mean 
Level 
243.58 3,7 
+ 30,0 
Chron. fast 
48,1 
Index 
- + 18,0 
4)243.58.51,7 
( + 24 + 1) 
/✓ // 
2,4= + 30,0 
Observed Z. D. 
- 60.59.42,9 
2 X 
Ref. and Parall. 
+ 1.36,8 
Semidiam. 
+ 15.46,4 
True Z. D. 
■= 61 . 17 . 6,1 
From the mean of the above observations, the chronometer 
appears to be 47*, 6 too fast, and the rate being — i‘,8i, we 
have 47‘,9 for its error too fast at noon. 
