OF THE SOLID CEUST OF THE EAETH. 
339 
§ 1. Data regarding Pendulum Observations in India. 
5. From the information furnished me by Colonel Walker I complete Table II. I 
have selected five stations on the Arc of Meridian at nearly the same distances from one 
another in succession, averaging about 5° 15' apart. I have also taken stations on the 
coast and on an island (Minicoy). Punnae is close to Cape Comorin. 
Table II. 
Table III. 
Geodetic coordinates. 
Observed 
numbers of 
vibrations at 
stations, re- 
duced for 
thermometer 
and baro- 
meter. 
Relative gravity 
freed from 
effects of height 
and latitude. 
Stations. 
North 
latitude. 
East 
longitude. 
Heights, 
in feet. 
Relative 
gravity. 
Reduction 
for height 
above sea. 
Allowance 
for latitude. 
Indian Are Stations. 
Punnae 
8 10 
o / 
77 41 
44 
85978-18 
1-0 0005074 
+ 42 
- 1062 
1-0-0006094 
Bangalore 
13 4 
77 37 
3007 
74 63 
1-00005900 
+2879 
- 2689 
1-00005710 
Damargida 
18 3 
77 43 
1934 
86-16 
1 -0 0003219 
+ 1852 
- 5050 
1-0-0006417 
Kalian pur 
24 7 
77 42 
1765 
86005 76 
1 + 00001340 
+ 1690 
- 8783 
1-0 0007753 
Kaliana 
29 31 
77 42 
826 
22-26 
1 + 00005177 
+ 791 
-12769 
1-00006801 
Coast Stations. 
Punnae 
8 10 
77 41 
44 
85978-18 
1-0 0005074 
+ 42 
- 1062 
1 —0-0006094 
Alleppy 
9 30 
76 20 
6 
81-23 
1 — O0004365 
+ 6 
- 1433 
1-0-0005792 
Mangalore 
12 52 
74 49 
7 
84-27 
1 -0 0003658 
+ 1 
- 2609 
1-0 0006260 
Madras 
13 4 
80 17 
27 
84-40 
1-00003628 
+ 26 
- 2689 
1-00006291 
Cocanada 
16 56 
82 18 
9 
93-56 
1-00001498 
+ 9 
- 4463 
1-0-0005952 
Ocean Station. 
Minicoy 
8 17 
73 2 
6 
82-31 
1-0-0004114 
+ 6 
- 1092 
1 _ 00005200 
6. The numbers of vibrations of the pendulum at the several stations differ from each 
each other for three reasons. The stations differ (1) in latitude, (2) in height above the 
sea, (3) in local attraction. Were all these allowed for, the numbers would come out 
the same for the several stations. In Table III. I allow for the influence of the first 
and second of these causes ; and the last column shows by its variations what we have 
to attribute to the third cause, viz. local attraction. 
The numbers in the first column of Table III. are obtained from those of the last 
column of Table II. by dividing them all by 8G000, and then doubling the small (that 
is, the decimal) part, because gravity varies as the square of the number of vibrations. 
In the second and third columns of Table III. the numbers are the last of seven places 
of decimals, the ciphers and the decimal point being omitted for convenience. The 
numbers in the third column are obtained by means of Clairaut’s Theorem, which shows 
that gravity varies as l+(f m—s) sin 2 /; the ellipticity being -^-g-g-. 
§ 2. Data regarding the contour of the Continent of India. 
7. Viewing the continent of India generally, and allowing for ridges of hills and 
hollows, it maybe said to lie more or less evenly, as far as this problem is concerned, up 
to the foot of the Himalayas. With regard to the Himalayas, by a careful examination 
of published documents and maps of the Great Trigonometrical Survey, and of Colonel 
R. Strachey’s map referred to in the Philosophical Transactions for 1858, p. 774, and 
