the vortices to be
in latitude 70d. There will be, in this case, a greater prevalence of
northerly winds _within_ this circle of latitude, to supply the drain to
the southward, and the back currents by passing above will descend at
the pole, partaking of the temperature due to that elevation. The
character of the arctic seasons may therefore be considered as partly
dependent on the average direction of the wind. Suppose again, the
extreme limits of the vortices to be about latitude 80d, the relative
areas of the two circles are as 4 to 1; so that in this last case the
exclusive range of the northerly winds is limited to one-fourth of the
first area. South of 80d the wind will frequently come from the south,
and by mixing with the local atmosphere of that latitude, will tend to
ameliorate the small area to the northward. And the greater atmospheric
commotion when confined to such a small circle of latitude, must assist
materially to break up the polar ice; which would tend still more to
equalize the temperature.

By referring to our table, we see that the mean conjunction of the pole
of the lunar orbit and the moon's apogee, was in longitude 128d on April
10, 1846, and let it be remembered that when the conjunction takes place
due south or in longitude 270d, the vortices attain their greatest
latitude north. When, on the contrary, the conjunction takes place due
north or in longitude 90d,[48] the northern limits of the vortices are
then in the lowest latitude possible.

Sir John Franklin sailed in May 1845, and was certainly at the entrance
of Wellington sound, near latitude 75d, April 3d, 1846, as the dates on
the graves testify. That season, according to the theory, was a cold
one; for the vortices could not reach so far to the northward in that
year, and consequently there were no storms, properly speaking. It would
probably be late in the summer of 1846, before the expedition was
liberated, and as the prevailing winds would be from the northward, he
would have little choice, but to stand to the westward if the state of
the ice permitted. In his instructions he was to use every effort to
penetrate to the southward and westward of Cape Walker, and he probably
conformed to them under the circumstances, and passed the winter in the
ice, in that neighborhood. And in 1847 we do not anticipate, from the
theory, that he would make much progress westward.

In 1848, Sir James Ross was sent out with the first relief-ship; bu