134 } Capt . Sabine’s observations on the magnetic needle. 
It is probable that the needle was affected by local attrac- 
tion either on the 9th or on the 19th of June; but on which 
day it is difficult to say. On the 9th the ships were anchored 
to an iceberg of very considerable size, on which the observa- 
tions were made, the instrument being removed as far as 
possible from the ships. On the 19th it was used in the 
observatory which was erected on Hare Island ; every fasten- 
ing of this ingenious and useful building was of brass, and 
the greatest care was taken to prevent the needle being dis- 
turbed by local or accidental causes. But there were several 
basaltic columns on the face of a hill which rose immediately 
from the observatory, which may have had an influence ; as 
these columns on Hare Island are said, by Professor Giesecke,* 
to have a powerful effect on the needle. 
Observations on the intensity of the magnetic force. 
Regent’s Park, London, April, 1818. By Captain Kater. 
Perpendicular to the meridian. 
too 
ICO 
8 21,6 
8 15 
Mean 
Account 
of vibra- 
tions. 
'OOOOOOOOOOO 
c - ChN O - WOO +N - 
0\ <-r\ tJ- r<-> N — — 
IOO 
00 
00 
No. of 
vibra- 
tions. 
OOOOOOOOOOO 
« N tn rj- r^OO ON O 
The subsequent observations were made by Captain 
Sabine. 
* Art. Greenland, Brewster’s Cyclopedia. 
