OF THE MAGNETIC DECLINATION AT POINT BAEKOW. 
505 
that the disturbances both at Point Barrow and at Toronto, when viewed in the a(j(jre(jate, 
have at each station two very marked and decided maxima in the twenty-four hours, one 
about 8 A.M., and the other towards midnight ; and that when the disturbances at Point 
Barrow are separated into their easterly and westerly constituents, the night maximum 
disappears in the easterly and the morning maximum in the westerly values, whilst the 
morning maximum of the aggregate values is found to consist almost wliolly of deflections 
towards the east, and the night maximum almost wholly of deflections towards the west. 
Now we may perceive by Table IV., that when the separation is made into easterly and 
westerly values, and the ratios of each class at the several hours to the respective units 
are computed, the phenomena at Toronto present an almost precisely corresponding 
arrangement, but with this essential difference, that the morning maximum of the 
aggregate values is due at Point Barrow to the great preponderance of easterly values, 
and at Toronto to the great preponderance of westerly values; and that the evening 
maximum of the aggregate values is, conversely, due to the great preponderance of 
westerly values at Point Barrow and of easterly at Toronto. 
The hours of least disturbance show also a much greater accordance when the easterly 
ratios at Point Barrow and westerly at Toronto are viewed together, than when any 
other comparison is made. The amount of disturbance diminishes as soon as the hour 
of noon is past, and continues comparatively small until much later in the evening than 
is the case in either the westerly disturbances at Point Barrow or the easterly at Toronto. 
WTiilst thus endeavouring to bring into view the several circumstances which seem to 
indicate a connexion subsisting between the disturbances of opposite character at Point 
Barrow and Toronto, it is well that we shoidd also notice one or two points in which, on 
the contrary, the easterly disturbances appear to agree with the easterly, and the westerly 
with the westerly better than either with the opposite. Thus, — 1st, the values of greatest 
comparative magnitude, Vz. those in which the proportion exceeds three times the 
average value, are easterly deflections at both stations, occurring however several hours 
apart, viz. at 8 a.m. at Point Barrow, and at 9 p.m. at Toronto. It is a consequence of 
this preponderance of easterly deflection at the two stations, (in the morning at the one 
station and in the evening at the other,) that the mean influence of the disturbances on 
the general cUrection of the needle is the same at both stations, viz. a small increase of 
east declination at Point Barrow, and a still smaller diminution of west dechnation at 
Toronto. 2nd, the highest values of the westerly disturbances at both stations show 
nearly an equal proportion to their respective units, viz. about 2^ times the mean hourly 
disturbance-value. The times of occurrence are also in this case very different, viz. at 
Toronto in the forenoon and at Point Barrow about midnight. At both stations the 
highest hourly values of the westerly deflections bear about an equal proportion in 
respect of magnitude to the highest easterly values. 
It would be obviously premature to attempt to connect the phenomena thus brought 
into view, and into comparison with each other, with such physical relations as might be 
imagined suitable to produce or to explain their accordances and differences. The points 
MDCCCLVII. 3 u 
