CAPTAIN ELLIOT’S MAGNETIC SURVEY OF THE INDIAN ARCHIPELAGO. 323 
D 5 by the method of deflection, and the result coincided with the value of q found 
by vibration. 
The following- Table contains the determination of the value of q, or of the coeffi- 
cient of temperature of the small magnets. 
T'— T 
qz=L r^ - ^lj in which t' and t are the two temperatures, andT' and T the corresponding 
times of vibration. 
Date. 
No. of 
magnet. 
No. of 
vibrations. 
T. 
t. 
No. of 
vibrations. 
T'. 
v. 
t'-t. 
T'-T. 
Value of q. 
1844. 
June 7. 
D5 
720 
86-5 
341-635 
3600 
121-3 
343'-05 
34-8 
1-415 
-000119 
Mean of the solid magnets 
May 28. 
D6 
1080 
86-6 
339-47 
1440 
116-8 
340-252 
30-22 
0-7825 
-000076 
y = -000105. 
A7 
720 
8625 
254-725 
720 
118-3 
256 
32 
1-275 
-0001565 
May 30. 
A8 
720 
86-5 
315-08 
1080 
119 
316-33 
32-5 
1 25 
-000122 
Mean of the hollow cvlindrieal 
May 30. 
AlO 
720 
87 
266-755 
1080 
120 
267-637 
33 
0-882 
-0001 
magnets -000322. 
June 7. 
H9 
360 
87 
180 3 
360 
113-8 
182 
26-8 
1-7 
-000352 
June 14. 
HIO 
360 
86-8 
181-92 
720 
126 
183-805 
29-2 
1-885 
-000355 
June 27. 
Hll 
360 
87 
172-96 
360 
103 
173-66 
16-0 
0-701 
-000253 
1845. 
April 7. 
C7 
756 
88-5 
423-1 
360 
109-7 
427-00 
21-2 
2-28 
-00025 
(3.) Moment of Inertia . — The moment of inertia was determined at different periods. 
The following Table contains the moments of inertia prior to the commencement of 
the Survey at the Singapore Magnetic Observatory. 
Date. 
Magnet. 
Small weights. 
Length 
of mag- 
net in 
feet. 
V'l or 
weight 
of 
cylinder 
in grs. 
r, or 
radius of 
cylinder 
in feet. 
Moment of 
inertia 
k,=^Pp+r‘i 
Large weights. 
Pi or 
weight 
of 
cylinder 
in grs. 
r, or 
radius of 
cylinder 
in feet. 
Moment of 
inertia 
'^-^7372- 
Radius 
of mag- 
net in 
feet, or 
Weight 
of mag- 
net in 
grs., or 
Pr 
Moment of 
inertia 
Time of 
1 vibration 
from 360. 
Needle 
loaded, 
Time of 
1 vibration 
from 360. 
Needle un- 
loaded, t. 
Time of 
1 vibration 
from 360. 
Needle 
loaded, t'. 
Time of 
I vibration 
from 360. 
Needle un- 
loaded, t. 
1845. 
// 
ilarch 7. 
D5 
6-9316 
3-7 
-3033 
210 
-01335 
3-863 
9-0289 
3-7 
414 
•01675 
3-862 
-0125 
497 
3-8294 
May 1. 
6-9678 
3-7202 
3-865 
9-0379 
37202 
3-862 
Vlarch IS. 
D6 
7025 
3-7266 
3-7972 
9-1661 
3-7266 
3-7934 
490 
3-7751 
May 2. 
7-022^ 
3-7249 
3-7931 
9-1526 
3-7249 
3-7995 
1844. 
August ... 
6-7881 
3-6097 
3-8236 
8-87276 
3-6097 
3 798 
6-7964 
3-6082 
3-8056 
8-8728 
8-6082 
3-7955 
6-7933 
3-607 
3-8158 
8-877 
3-607 
3-7882 
March 17. 
A5 
5-355 
2-6958 
-2522 
2-2798 
7-0458 
2-6958 
2-2779 
418 
2-232 
1845. 
Marcli 18. 
A6 
6-1154 
3 0733 
2-2693 
8-0533 
3-0733 
2-2641 
416-5 
2 224 
19. 
A7 
5-4478 
2-74 
2-2742 
7-18 
2-74 
2-2641 
416-5 
2224 
22. 
A8 
6-5843 
3-2933 
2-2408 
8-2758 
3 2933 
2-2366 
411 5 
2-197 
24. 
A9 
5-657 
2-81 
2-19.98 
7-4661 
2-81 
2-1920 
405-5 
2- 165 
25. 
AlO 
5-7172 
2-8664 
2-2551 
7 5372 
2-8664 
2-2)58 
415 
2-216 
26. 
C7 
5-7533 
4-4194 
-3350 
17-014 
6-8027 
4-4194 
17-191 
The following Table contains the results of the values of found for each 
needle; the mean value of %^k determined from observations prior to 184/ being- 
considered as of value equal to those taken subsequently. 
Date and Station. 
Value of ir^Afor the eyliudrical magnets and the collimator magnet. 
D5. 
A 7. 
A 8. 
A 9. 
A 10. 
C7. 
Singapore, prior to 1847 
Batavia, July, 1847 
Singapore, F^ruary, 1848 
Singapore, December, 1848 
Madras, September, 1849 
38*225 
38*265 
38*482 
38*423 
38*208 
22*485 
22*443 
22*353 
22*296 
22*884 
22*281 
22*140 
22*124 
22*126 
21*846 
21*818 
21*882 
21*797 
21*783 
21*813 
22*394 
22*363 
22*385 
22*307 
22*383 
168*14 
167*30 
166- 94 
167- 25 
2 T 2 
