37 6 Capt. Rater's experiments for determining the variation 
From the preceding Tables were deduced the following 
vibrations in a mean solar day. 
By the Stars. 
Arbury Hill. 
Correct 
No. of 
Interv. 
From 
To 
Vibrations in a 
Stars 
of 
mean solar day. 
observed 
Transits. 
22 A. M. 
25 P. M. 
86056,86 
3 
4 
22 A. M. 
26 P. M. 
86056,88 
3 
5 
26 A. M. 
26 P. M. 
86056,96 
3 
I 
By the Sun. 
21 P. M. 
26 A. M. 
86056,89 
2 
J 5 
From the number of stars observed, and the intervals of the 
transits, we derive 86056,88 for the mean by the stars, 
86036,89 by the sun, and 86056,88 for the final mean num- 
ber of vibrations in 24 hours. 
The barometer being at 29,55 inches, and the thermometer 
at 5 Q °>9 we have 6,04 for the correction on account of the 
buoyancy of the atmosphere. 
The angle of elevation of the top of the tent on Arbury 
Hill, taken by the repeating circle from the station where the 
clock was placed, was found to be i°.28 , .2i' / ,4 ; and as it will 
appear in the Appendix, that the distance from the station on 
Arbury Hill to the clock, was 3048 feet, we have 78 feet very 
nearly for the elevation of the top of the tent above the pen- 
dulum. The elevation of Arbury Hill above the sea, as deter- 
mined by the Trigonometrical Survey, is 804 feet, from which 
deducting 67 feet, (the height of the tent being 11 feet,) we 
obtain 737 feet for the elevation of the pendulum above the 
