LIEUT.-COLONEL SABINE ON TERRESTRIAL MAGNETISM. 
133 
* The 24th and 25th of September were days of great and general magnetic disturbance. If we collect in 
one view the determinations of the horizontal force at Macao, we find them as follows : — 
1841. April 9 six needles — 7 - 596 
April 12-19 six needles — 7'595 
September 24 and 25 six needles — 7 '634 
November 16-20 .... six needles — 7'585. 
The comparison of these results leaves little reason to doubt that the discrepancy on the 24th and 25tli of Sep- 
tember was occasioned by an irregularity in the horizontal force itself ; and we may infer that the derangement, 
which was felt at all stations at which magnetic observations were made on that day, was characterized at 
Macao by an increase of the horizontal force at the hours when Sir Edward Belcher’s observations were 
made. These hours appear to have been, late in the afternoon of the 24th, and from 11 a.m. to 3 p.m. on 
the 25th. 1 
