SOUTHERLY DRIFT OF ICE. 
1S3 
these agencies, and it is quite reasonable to suppose 
any other feasible cause. Passing over the discovery 
of 64° F. at this depth, we still have to account for 
the water of 42° F. flowing southwards, as evidenced 
by the increase of its temperature as we proceeded 
northwards. 
It is clear that this question of temperature requires 
further investigation; and it is also clear that what¬ 
ever the result may be, it will materially affect all the 
prevailing theories respecting oceanic currents. It is 
not improbable that this warm water flows from the 
circumpolar region; and if so it would indicate a cir¬ 
cumpolar sea. 
Many facts are known which are consistent with 
this view. Every year the edge of the pack-ice, and 
the ice-fields themselves, break up and drift south, 
at a rate sometimes equal to thirteen miles a day, as 
found by Captain Parry. This does not occur when 
the northern ocean is wholly covered with ice, in the 
winter season. The drifting of the ice (as also cur¬ 
rents) implies a sea free of ice somewhere in the 
north, occupying an area at least as extensive as the 
drift-ice. As has been seen, some of the ice is the 
result of more than one year’s growth ; and as the ice 
travels southerly, say, from four to thirteen miles or 
more per diem, a similar area of open sea must be 
simultaneously forming round the pole, the ice-holes 
