181 
Natural Philosophy, ’--^Astronomy, 
which would produce an alteration. The whole of my proceed- 
ings are laid open to every astronomer, in the seventh number of 
my Observations ; and those who devote to them an attentive 
examination, will have greater confidence in what 1 have stated, 
than by listening to any idle reports.” 
5. Anomaly in the Observations at Arhury Hill , — In levelling 
from the station of Arbury Hill to the Grand Junction Canal, 
Mr B. Bevan found that the country to the north of Arbury sta- 
tion fell suddenly about 400 feet, and continued at this de- 
pressed state for nine or ten miles. He therefore conceived that 
this defect of matter to the north of the station was a reason for 
supposing a deflexion of the plumb line to the southward. In 
order to ascertain the truth of this supposition, he computed the 
latitude of Arbury station from that of Blenheim, determined 
independent of any astronomical observation made at Arbury, 
and he found it Jive seconds less than that shewn by the zenith 
sector ; thus countenancing, in a high degree, the probability of 
local attraction by the high land to the south of the station. See 
this Journal, vol. i. p. 200. 
The following are the heights of the station which he found 
by levelling. 
Mr Bevan. 
Col. Mudge. 
Feet. 
Feet. 
Diff. feet 
Wendover station, 
861 
905 
44 
Kensworth, 
8094 
904 
944 
Bowbrickhill, 
5714 
683 
1114 
Arbury Hill, 
7404 
804 
644 
See Phil. 
Trans. 
1823, p. 
6. Sir Thomas Brisbane's Experiments on the Pendulum . — 
By means of a pendulum belonging to the Board of Longitude, 
and similar to that used by Captain Kater and Captain Hall, 
Sir Thomas Brisbane made a series of experiments at Paramatta, 
in 1822. The pendulum having been swung in London, and 
observed both by Captain Kater and Sir Thomas Brisbane, it 
was found that it performed 86090.17 vibrations at London, in 
Lat. 51° 31' 8".4, in a mean solar day, at 60° of Fahrenhdt, 
and in a vacuum. At Paramatta, in E. Long. 151° 0' 15", and 
S. Lat. 33° 48' 43", the same pendulum performed 86021.59 
