204 
this was the case. ‘To discover an alteration there would be 
need to remeasure the base line after an interval of time 
had elapsed. 
Professor CHALLIS said it had been stated that there was 
an abnormal deviation of the plumb-line south of the Hima- 
layas, and asked whether this had been observed on the north 
also, where, according to Col. Walker, some surveys had re- 
cently been made. 
Col. WALKER said the surveys on the north side were too 
rough to be of value for geodetic purposes. On the south side 
of the pendulum observation shewed a deficiency of density 
as the hills were approached, and an increase on proceeding 
southwards towards the sea. 
Some conversation followed, in which Prof. Adams, Prof. 
Miller, and Col. Walker took part. 
February 27, 1871. 
The PRESIDENT (PROFESSOR CAYLEY) in the Chair, 
Communication to the Society. 
On Observations made at San Antonio on the Total 
Solar Eclipse of 22 Dec. 1870. By W. H. H. Hup- 
son, M.A, St John's. 
I propose to lay before the Cambridge Philosophical Society 
some account of the recent English expedition to observe the 
Total Eclipse of the Sun, which occurred on the 22nd of Dee. 
1870. 
This is not the place to describe the difficulties which had 
to be surmounted before the expedition could start at all—how 
some one had blundered and sent in the application to the 
wrong department—the natural rebuff received from a govern- 
ment subordinate—the unphilosophical huff thereat—the sus- 
