in the length of the pendulum vibrating seconds. 369 
when first applied, and I can in no way account for the acce- 
leration in the rate of the clock, but by supposing, that whilst it 
was at rest, the external surface of the oil had become thick- 
ened by some action of the sea air upon it. This would of 
course occasion the rate to be less, on the clock being first 
put up, and a gradual acceleration would afterwards take place 
as the thick coat of the oil became blended with the more 
fluid particles beneath. These remarks may perhaps warrant 
the important inference, that no reliance whatever can be 
placed on results obtained by means of a pendulum attached 
to a clock, and that until oil can be banished from chrono- 
meters, and the maintaining power be such as to be equal 
under all circumstances, we may spare ourselves the trouble 
of attending to other sources of error. 
The clock being cleaned, the observations were made and 
the results deduced which are contained in the following 
Tables. 
Transits observed at Leith Fort. 2d Series. 
Stars. 
September 8. 
September 10 . 
September 12 . 
September 14. 
a. Equulei 
j 3 Aquarii 
£ Pegasi 
0 Aquarii 
Pegasi 
x. Aquarii 
£ Pegasi 
| Pegasi 
a Pegasi 
h. m. s. 
10. 2.39,48 
10.17.53,83 
10.31. 6,30 
10 49.44,22 
11.14.25,06 
11.24 5.68 
11.28. 0,69 
1 1.33. 18,73 
11.51.21,57 
h. m. s. 
9.55.54,46 
10.11. 8,88 
10.24.21,36 
11. 7.39,80 
1 1 .17.20,66 
1 1.21.21,70 
1 1.26.33,72 
11.44.36,50 
h. m. s. 
9. 49. I 1,23 
10. 4.25,60 
10.36.16,20 
11. 0.56,53 
1 1 . 1 0 - 37 - 3-8 
1 1.14.38,28 
H.19.50,34 
1 1 - 37*5 3»3 3 
h. m. s. 
9.42.28,05 
10.10.54,92 
10.29.32,78 
10.54.13,42 
11. 3 ,C 4 , 3 z 
II. 7.55,24 
11.13. 7*4° 
1 1.31.10,33 
3c 
MDCCCXIX. 
