CXXX1V 
APPENDIX. 
moved in Azimuth until the Zeros of the ring coincided with it, when the 
Needle being removed, and a brass bar subsituted in the stirrup, all twist 
was taken out of the silk, and the point of suspension adjusted (it having 
a motion for that purpose) until the brass bar rested in the same direction as 
the Needle had done; the Needle being then replaced, was drawn by a 
magnet 60° from its natural direction, released, and suffered to vibrate until 
the arcs became too small to be discerned ; the time and arc being noted at 
each tenth vibration. 
The whole instrument was of brass ; the silk line consisted of as few fibres 
of raw silk as were sufficient to support the weight of the Needle, the length 
of the suspension being about nine inches. 
May 1819. On the Sea Beach at Sheerness, Latitude 51° 26' N., Longitude 44° O' W., 
Dip of the Needle 60° 55' N. 
No. of 
Needle 1 
Needle 
2 
Needle 3 
Vibrations 
Arcs 
Interval 
Arcs 
Interval 
Arcs 
Interval 
Arcs 
Interval 
0 
M 
S 
O 
IVI 
S 
O 
M 
S 
O 
M 
S 
60 
60 
60 
60 
10 
48.5 
1 
39 
47 
1 
34.5 
42 
1 
29.5 
44 
1 
30 
10 
39 
1 
37 
37.5 
1 
32.5 
33.5 
1 
27.5 
35 
1 
28 
10 
32.5 
1 
37 
30.5 
1 
31.5 
26.5 
1 
26 
28.5 
1 
27 
10 
27 
1 
35.5 
25 
1 
30.5 
21 
1 
26 
23 
1 
26 
10 
23.5 
1 
35 
22 
1 
31 
17 
1 
25 
19 
1 
26 
10 
20.5 
1 
34.5 
17.5 
1 
30 
14 
1 
24.5 
16 
1 
25.2 
10 
16 
1 
34.5 
12.5 
1 
30 
10 
1 
24.5 
12 
1 
25.3 
10 
14.5 
1 
34.5 
12 
1 
30 
7.5 
1 
25 
10.5 
1 
25 
