272 The Proposed Pendulum Operations for India. [No. 4, 
The Indian operations will eventually be combined with those taken 
previously with similar instruments in other parts of the world, to 
deduce the ellipticity of the earth’s mean figure. Both Sir John 
Herschel and Professor Stokes have remarked, in their letters on the 
proposed Indian operations, that almost all observations hitherto made 
have been taken at stations either on islands or coasts, so that a series 
along the centre of a continent is very much needed. A complete set 
of observations has been already taken at the Kew observatory by 
Mr. B. Loewy, with the Indian apparatus; and on the completion of 
the experiments in this country it will be returned to Kew, in order 
that final observations may be taken, to show whether the pendulums 
have undergone any change in the interim. 
It is to be hoped, however, that so good an opportunity will not be 
lost of extending these observations to stations easily accessible from 
India, though not included within its limits. On this head Professor 
Miller’s opinion may be quoted at length, ‘“‘ Much would be added to 
the value of the observations made at the stations of the Indian 
survey, if, before the pendulums were brought back to England, 
observations could to be made with them at some other points, especially 
points nearer tothe equator, such, for instance, as the south coast of 
Ceylon, Singapore, or on the coast of Borneo. Another accessible 
point, interesting from being in a long line of depression, where a 
large gravitation might be expected, is Aden.” 
The intention of the Russian government, to have similar obser- 
vations made along the Russian arc, has already been alluded to. 
If, after the return of the pendulums to England, they were to be 
swung at one of the Russian stations, it will be possible to combine 
the Russian with the Indian operations, and deduce a value of the 
earth’s ellipticity from exclusively Continental observations, extending 
from cape Comorin to the northernmost part of Finmark. 
“gravitation, Actually to carry this out, would probably require observations 
“to be made at stations more numerous than can be thought of, but the fact of 
“its possibility shows how severe a check pendulum observations are capable of 
“ exercising on the results of geodetic observations.” 

