experiments made with an invariable pendulum, &c. 315 
the atmosphere, ai)d 86090,17 (the same as the former re- 
sult ) , for the number of vibrations which would be made by 
the pendulum at London in latitude 5i°3i'8 ",4 in a mean 
solar day at the temperature of 6o°, and in a vacuum. 
From a slight sketch and an accompanying description, 
every care has evidently been taken by Sir Thomas Brisbane, 
that no suspicion of a want of solidity should attach to the 
support built for the pendulum at Paramatta. This is con- 
structed of solid masonry, upwards of five feet in width, on 
a foundation five feet below the level ground, and is insulated 
from the floor. The square part of the cast iron frame, to 
which the bell-metal support of the pendulum is attached, is 
let into a stone nearly six inches thick, which surmounts the 
whole mass. 
The following are the details of the observations made 
by Sir Thomas Brisbane at Paramatta, the latitude being 
33 0 48' 43" south, and the longitude 151 0 o' 15" East from 
Greenwich. 
FIRST SERIES; 
August 27 th, 1822 . Paramatta. 
Clock going mean time. Barometer 29,55 Inches. 
Temp. 
Time of 
coincidence. 
Arc 
of Vibra- 
tion. 
Mean 
Arc. 
Interval 
in Seconds. 
No. of 
Vibra- 
tions. 
0 bserved 
Vibrations 
in 24 hours. 
Correc- 
tion for 
Arc. 
1 Vibrations in 
24 hours. 
53,0 
53,4 
h. m. s. 
7 15 56 
23 24 
30 53 
3S 24 
45 53 
53 22 
8 0 52 
8 23 
15 52 
23 20 
30 49 
0 
1,52 
1,48 
1,42 
1,37 
1,34 
1,29 
1,23 
1,20 
1,17 
1,13 
1,08 
O 
1,50 
1,45 
1,39 
1,35 
1,31 
1,26 
1,21 
1,18 
1,15 
3,10 
448 
449 
451 
449 
449 
450 
451 
449 
448 
449 
3,70 
3,45 
3.17 
2,9S 
2,82 
2,61 
2,40 
2,28 
2.17 
1,98 
53,2 
Mean 
449,3 
447,3 
86015,40 
2,76 
86018,16 
