562 



Br. W. B. Carpenter on the 



[June 13, 



39. If the views I have propounded be correct, it may be expected that 

 near the border of the great Antarctic Ice-barrier, a Temperature below 30° 

 will be met with (as it has been by Parry, Martins, and Weyprecht 

 nearSpitzbergen,§ 15) at no great depth beneath the surface; and that instead 

 of rising at still greater depths, the thermometer will fall to nearly the 

 freezing-point of salt water. The greater the distance from the ice-barrier, 

 the greater would be the depth at which the surface of the Glacial stratum 

 would be met with ; but in consequence of the free communication between 

 the Antarctic area and the great Southern Oceans, it may be expected that 

 the deepest parts of these will be fcund to show a temperature as low as 

 32°, or perhaps lower, even near the Equator. — The bottom-temperature of 

 the North Pacific will afford a crucial test of the truth of the doctrine. 

 For since the sole communication of this vast Oceanic area with the Arctic 

 basin is a Strait so shallow as only to permit an inflow of warm surface- 

 water, its deep cold stratum must be entirely derived from the Antarctic 

 area ; and if its bottom-temperature is not actually higher than that of the 

 South Pacific, the glacial stratum ought to be found at a greater depth 

 north of the Equator than south of it. In the North Atlantic, again, the com- 

 parative limitation of communication with the Arctic area may be expected 

 to prevent its bottom-temperature from being reduced as low as that of the 

 Southern Atlantic. But it will be a matter of peculiar interest to determine 

 the bottom-temperature of the deep channel that separates Greenland and 

 Iceland, to ascertain the thickness of the Glacial stratum which (I venture 

 to predict) will be found to occupy a large proportion of its entire depth, 

 and to trace the gradual thinning-out of this, as it diffuses itself over the 

 vast area of which the bottom-temperature is reduced by it. 



40. It will further be extremely important to ascertain by Mechanical 

 means, if possible, whether this Glacial flow has a movement of which the 

 direction and rate are determinable. And I would especially point out that 

 the " Lightning Channel " (§ 14) affords a peculiarly favourable opportunity 

 for such investigation, in consequence of the well-marked distinctness of its 

 two strata. If my view be correct, a " current-drag" suspended in the upper 

 stratum ought to have a perceptible movement in the N.E. direction ; 

 whilst another, suspended in the lower stratum, should move S.W. And 

 though the rate of movement in each may be very slow, yet the opposition 

 of their directions may be expected soon to make itself apparent, in the sepa- 

 ration of the surface-buoys from which the drags are suspended. — Should 

 the examination of this Northern portion of the Oceanic area be beyond the 

 scope of the Circumnavigation Expedition, I would urge that it should be 

 undertaken by any Polar Expedition which the British Government may 

 fit out. For the difference in the Thermal conditions of the Northern and 

 Southern Oceans, consequent upon the difference in their respective relations 

 to the Arctic and Antarctic basins, is a question of peculiar interest in a 

 Geological point of view. 



41. If, again, as may be anticipated, it should prove that a considerable 



