in the 'length of the pendulum vibrating seconds . 371 
By the Stars. Leith Fort, ad Series. 
Correct Vibrations 
Interv. 
From 
To 
in a 
Mean solar day. 
No. of stars 
observed. 
of 
Transits. 
9 A.M. 
10 P. M. 
86073,09 
8 
2 
9 A. M. 
12 P. M. 
86073,12 
8 
4 
9 A.M. 
14 P. M. 
86073,13 
8 
6 
11 A.M. 
12 P. M. 
86073,14 
7 
2 
11 A. M. 
14 P. M. 
86073,16 
7 
4 
13 A. M. 
14 P. M. 
86073,17 
7 
2 
Using the number of stars observed, and the intervals be- 
tween the transits as before, we have 86073,13 for the number 
of vibrations in 24 hours. 
The barometer being at 30,01 inches, and the thermometer 
at 54 0 , 3 the correction for the buoyancy of the atmosphere is 
6,11. 
This correction, together with 0,18, the correction for the 
height above the sea, being applied, we obtain 86079,42 for 
the number of vibrations made by the pendulum in vacuo* as 
deduced from the second series, from which the result of the 
first series differs 0,05 of a vibration. The mean of both is 
to be preferred. 
Operations at Clifton. 
On the 17th of September I left Edinburgh, and proceeded 
to Clifton in Yorkshire ; at which place my instruments and 
party arrived on the 28th. Here I was so fortunate as to meet 
with a vacant house in the village, perfectly suited to my pur- 
pose, belonging to Mr. Milward, who is also proprietor of 
the field in which is the station of the Trigonometrical Survey. 
Previous to the commencement of my experiments, the clock 
was carefully cleaned. The observations were then made, and 
