68
HISTORY OF THE
[1830-40
period of stagnation. As regards astronomy of precision, this
rise is more connected with the name of Airy than with any other.
When Airy took charge of the Cambridge Observatory in 1828,
he determined at once that the planets were to be observed as
often as possible. At Greenwich they had been completely
neglected by Maskelyne, who only observed the sun, the moon,
and his 36 standard stars, and they had been very little looked
after by Pond. Airy now began to observe them regularly at
Cambridge, and also showed his interest in them in other ways ;
by his suggestion that the mass of the moon might be determined
by observations of Venus near inferior conjunction,* and by his
new determination of the mass of Jupiter.f Having realised the
value of regularly continued observations of the major planets,
Airy soon saw the importance of getting the Greenwich planetary
and lunar observations made since 1750 reduced and compared
with the tables. These two great undertakings were not finished
till the following decade.
The four minor planets known at that time continued to attract
very little or no attention in England, while they were, as in previous
years, regularly observed and their orbits computed in Germany.
The same was the case with comets ; only Halley’s comet excited
a great deal of interest at its return in 1835. Of researches on
planetary perturbations we cannot speak here, since none were
published by the Society, but it was during this period that
Lubbock published a series of important memoirs on lunar and
planetary theory, possessing many novel features.
In order to find a more correct value of the ellipticity of
the earth by means of pendulum-observations in high southern
latitudes and near the equator, the Admiralty sent out the
sloop Chanticleer under Commander Henry Foster, R.N., in 1828.
On several previous voyages, Foster had made pendulum experi
ments and taken other observations, for which he received the
Copley Medal in 1827. He had served in the Hecla on Parry’s
third Arctic voyage. His work in the Chanticleer had nearly
been completed when Foster was unfortunately, in 1831 February,
drowned in the River Chagres. His observing books and papers
were by the Admiralty handed to Baily, who had been partly
responsible for Foster’s outfit. In addition to two of Kater’s
invariable pendulums, Foster had taken with him two convertible
ones furnished with two knife-edges ; these were the property of
the Society ; they had been designed by Baily, and had been ad
justed and tried by him.J This led him to investigate all possible
* Memoirs, 4 , part 2, p. 235 ; M.N., 1 , 140.
f Memoirs, 6, 83 ; 8, 33 ; 9 , 7 ; 10 , 43 ; M.N., 2 , 171 ; 3 , 36, 113 ; 4 , 25.
j Described in Monthly Notices, 1 , 78.