77 
magnetic al observations at Port Bowen , &c. 
1825 
A. M. 
P. M. 
January - 
6 h oo ra - - 
- 4 h OO m 
February 
6 30 - 
4 OO 
March - 
- - 5 30 - - 
- 5 00 
April - - 
- - 7 00 - 
-53 0 
Mean 6 15 
4 37 
To avoid the insertion of many useless figures in the 
tables, the resulting amount of easterly or westerly defection on 
each side of the zero has been computed. 
The maximum westerly variation at Port Bowen appears, 
from these observations, generally to have occurred between 
the hours of io h A. M. and i h P. M., the mean result of one 
hundred and twenty days* observations being n h 49 ra A. M. 
The minimum westerly variation, or the greatest deflection 
of the north end of the needle to the eastward, took place 
between 8 h P. M. and 2 h A. M., the mean time, deduced as 
above, being io h i m P. M. 
In a few instances the maximum deflection of the needle 
to the westward occurred as early as 8 h A. M., and as late as 
3 h P. M. ; and in like manner, the greatest deflection east- 
ward took place at 2 h and 3 h P. M., on some few occasions. 
In all these anomalous cases, however, it was remarked, 
from simultaneous observations on the times of vibration 
of a suspended horizontal needle, that these irregularities 
were evidently due to an extraordinary alteration in its in- 
tensity, which produced a deflection contrary to the regular 
order of the motion of the needle. 
The diurnal change of direction appears, by these obser- 
vations, to have been seldom less than one degree, and some- 
times to have amounted to 5, 6, and even 7 degrees, and 
there can be no doubt that the changes in this amount were 
