CAPTAIN ELLIOT’S MAGNETIC SURVEY OF THE INDIAN ARCHIPELAGO. 319 
Year and Month. 
Name of Station. 
No. of 
Needles. 
No. of Dip 
Circles. 
No. of 
observa- 
tions. 
Mean value 
of the Dip. 
Probable error 
of a single 
determination. 
Probable error 
of the mean 
value. 
IVTaroh, 1 846 
Sinffaoore 
3 
1 
21 
— 12 47-7 
+ 4*3 
+ 0*9 
July, 1846 
Sambas 
o 
r 
3 
1 
6 
14 26-5 
4-2 
1*7 
Pantianak ... 
3 
1 
9 
14 41-0 
3-3 
1*1 
May and June ... 
Sarawak j 
3 
1 
27 
11 09-7 
4-9 
0-9 
September, 1846 
Batavia 
3 
1 
9 
27 03-7 
3-1 
1-0 
November 
6 
3 
6 
27 02-4 
2-0 
0-8 
November 
Tegu 
12 
3 
19 
28 42-5 
1-8 
0-4 
November 
Top of Gede 
5 
2 
6 
29 42-7 
1-8 
0*7 
Deeemher 
Chuniur 
12 
3 
12 
28 23-1 
2-4 
0*7 
December 
Sidang Barang 
4 
1 
8 
30 12-1 
1-3 
0*4 
December 
Bandong 
11 
3 
15 
28 31-1 
0-8 
December 
Garoet 
6 
2 
6 
28 58-5 
0-7 
0-3 
December 
Permangpek 
4 
1 
8 
30 11-8 
0-9 
0-3 
February, 1847 ... 
Soorabaya ... 
4 
1 
8 
28 50-2 
3-8 
1-3 
March, 1847 
Sumenap 
4 
1 
12 
27 43*5 
1-3 
0-4 
April 
PuloKuneeang 
4 
1 
12 
27 23*6 
2-3 
0*7 
May 
Kedeeri 
4 
1 
1 
29 50-0 
2-1 
0-6 
.Tiilv 
Batavia 
9 
3 
44 
27 08-2 
1-8 
0-3 
September 
Bencoolen 
9 
3 
17 
23 53-1 
1-9 
0-5 
October 
Padanff 
9 
3 
9 
18 31-7 
3*9 
1*3 
February, 1848 ... 
Singapore, a.m. 
4 
1 
28 
12 56-4 
2-0 
0*4 
P.M. 
4 
1 
28 
12 57-2 
1-9 
0-4 
4 
1 
56 
12 56-8 
2*0 
0-3 
May 
Pulo Labooan . 
9 
3 
9 
2 53-2 
1-7 
0-6 
Sambooanga . 
9 
3 
9 
+ 1 19-3 
1-6 
0*5 
June 
Keemah 
9 
3 
9 
— 11 02-7 
1*7 
0*4 
August 
Cocos 
9 
3 
36 
39 20 
1-3 
0-2 
November 
Sinffaoore 
9 
3 
80 
12 59-4 
2*8 
1-3 
January, 1849 ... 
Malacca 
9 
3 
9 
11 27-9 
0*9 
0-3 
January 
Pulo Dinding . 
9 
3 
9 
7 33-9 
2-2 
0*7 
January 
Penang 
9 
3 
9 
4 55-5 
1*6 
0*4 
February 
Nicobar 
9 
3 
9 
+ 1 17-8 
1-1 
0*4 
March 
Hastins's’ Island 
9 
3 
9 
4 32-3 
1*9 
0*6 
April 
Moulmein 
8 
3 
8 
17 49*1 
2*5 
0-9 
July 
Madras 
9 
3 
29 
7 37'7 
1-5 
0-3 
Horizontal Intensity. 
The horizontal intensity was determined from four declinometers, viz. the small 
Observatory Declinometer at Singapore ; the Induction or No. II ; Jones’s or No. 
Ill ; and the Portable Declinometer. 
The Observatory Declinometer \vuth apparatus, consisted of a small gun-metal 
box, in which was suspended a needle 3 inches in length with mirror attached : two 
deflecting bars at right angles to the box, were marked off to 0’05 of a foot. A tele- 
scope and scale detached from the instrument, and put on a separate pillar, completed 
the apparatus, which was placed in a building near the magnetic observatory. 
2nd. The Induction or No. II. Declinometer . — This instrument has already been 
described ; the apparatus for deflection consists of two arms fixed at right angles to 
the box ; they were of insufficient length, as the greatest distance at which the deflect- 
ing magnet could be placed was 1*4 foot. On measuring the angles of deflection. 
