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.