179 
Natural Philosophy. — Astronomy. 
Table I. column’ 1: is deduced by taking the difference be- 
tween NPD 1755'^ and the NFD 1800-f, and reducing the 
rate for 10 years, for change of precession, to 1818. 
Column % in like manner, from Palermo j Cat. 1800, and , 
Dublin Cat. 1823 §. 
Mr Pond’s observations 1800 were made at Westbury \\. 
There are two ways of considering the results in the above 
Tables. 
(1.) Mr Pond deduces, that the variations inNPD are irregular; 
and he supports his conclusion by the observations from which 
the numbers in Table 2. are computed. If his observations are 
exact, this remarkable consequence follows, that the errors of 
observation at Palermo and Dublin have made the variations in 
Table 1. appear constant, which are really changeable. 
(2.) If we consider Table 1. as supporting an uniform varia- 
tion in NPD of each star, and there is no greater differences 
than what might be expected from the unavoidable errors of 
observations, then it follows, that the Palermo and Dublin obser- 
vations are more exact than the Westbury and Greenwich ob- 
servations. 
2. Comet of September 1822, observed at Paramatta. — The 
following are the elliptic elements of the comet observed at 
Paramatta by Sir Thomas Brisbane and Mr Rumker, as com- 
municated to the Royal Society of Edinburgh. 
Time of passing the perihelion, mean time, 
Log. of perihelion on the orbit, ) 
Log. of descending node j 
Inclination, . , 
Logarithm e, Q = 82° 53' 11"), 
Log. 4 parameter. 
Sidereal revolution in days, 
from mean equinox, 
Oct. 24,221201 
/ 271° 36' 18".3 
(272 42 23 
52 40 41 
9.9966440 
0.3585731 
663554.3 
3. Anomaly in the Figure of the Earth.So many ships 
touch at Madeira, and take a new departure from it, that the 
longitude of the island is a matter of considerable importance. 
Dr Tiarks was therefore sent out by the Board of Longitude to 
* Bessel, Astron. Fundament. -f Piazzi, Great Catalogue of 1^14^. 
$ Journal of Science, Sept. 1822. § Pldl. Trans. 1806. 
U For Mr Pond’s Observations, see Phil. Trans. 1815, and 1823, Part 1. 
