360 Capt. Kater’s experiments for determining the variation 
The mean height of the barometer during the experiments, 
was 30,09 inches, and the mean temperature 6o°,8, from 
which data, and the specific gravity of the pendulum, we have 
6, 04 for the correction, on account of the buoyancy of the 
atmosphere. 
Applying these corrections to the mean number of vibra- 
tions before found, we obtain 86086,01 for the final number 
of vibrations which would be made by the pendulum in a 
mean solar day, in vacuo, and at the level of the sea. 
The rate of the clock having suffered a continual accelera- 
tion, as I have before stated, it became a subject of anxious 
importance to determine what effect this might possibly have 
on the result of the experiments ; particularly as the same 
curious circumstance had taken place at Unst, at which station 
however the unfavourable weather prevented the commence- 
ment of my observations, until the acceleration had nearly 
attained its maximum. To satisfy myself on this point, I took 
down the clock on the 13th August, and having carefully 
cleaned it, began a new series of observations, which are 
given at large in the Appendix, and from which the following 
tables and results are derived : 
Transits observed at Portsoy. 2d Series. 
Stars. 
August 13. 
August 14. 
August 15. 
August 16. 
August 17 . 
August 18 . 
August 19 . 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
h. m. s. 
The Sun 
0.1 1.47,72 
— 
0.12.49,27 
0.13.19,72 
0.13.49,88 
— 
0.14.49.28 
Arcturus 
4.48.35,44 
— 
4.42. 6,66 
4 - 3 8 - 53 A 7 
— 
4.32.25,84 
— 
a. Ophiuchi 
8. 7.17,18 
8. 4. 2,83 
8. 0.48,78 
7.57.34,88 
7 - 54 -zi >23 
— 
v Ophiuchi 
— 
8.26.31,46 
8.23.16,94 
8.16.49,55 
8 13.36,30 
— 
5} Serpentis 
— 
8.49.21,19 
8.46. 7, 0 
8.42.53,09 
8 - 39 - 39>77 
8.36.26,36 
— 
a Lyrse 
— 
9. 8.11,68 
9. 4 * 57*5 9 
9. 1.43,81 
8.58.30,19 
8.55.16,39 
— 
ij. Aquilse 
10. 2.29,88 
— 
9.52.48,21 
— 
— 
a Aquils 
*" 1 
10.19. 9,84 
— 
“ 
10. 9.28,18 
— 
“ I 
