8 



Passed Alidshipman S. P. Gr:ffin, who commanded the Brig " Rescue," in the American searching expe- 

 dition after Sir John Franklin, informs me that one occasion the two vessels were endeavoring to warp up to 

 the northward in or near Wellington channel, against a strong surface current, which of course was setting to the 

 snulh ; and that while so engaged, an iceberg with its top many feet above the water, came " difting up," 

 from the south, and passed by them " like a shot," although they were stemming a surface current against 

 both the berg and themselves. Such was the force and velocity of the under current, that it carried the berg 

 to the northward faster than the crew could warp the vessel against a surface but counter current. 



Capt. Duncan, Master of the English whale ship Dundee, says, at page 76 of his interesting little narrative : 

 "Dec. I8th, (1826) — It was awful to behold the immense icebergs working away to the northeast from us, 

 ami not one drop of water to be seen ; they were working themselves right through the middle of the ice." 

 And again at page 92, &c: 



" Feb. 23d— Latitude 68° 37', N. Longitude about 63° W. 



" The dreadful apprehensions that assailed us yesterday by the near approach of the iceberg, were this 

 day most awfully verified. About 3 P. M. the iceberg came in contact with our floe, and in less than one 

 minute it broke the ice ; we were frozen in quite close to the shore ; the floe was shivered to pieces tor several 

 miles, causing an explosion like an earthquake or one hundred pieces of heavy ordnance fired at the same 

 moment. The iceberg, with awful but majestic grandeur, (in height and dimensions resembling a vast moun- 

 tain,) came almost up to our stern, and every one expected it would have run over the ship. * * » 



" The iceberg, as has been before observed, came up very near to the stern of our ship ; the mtermediate 

 space between the berg and the vessel was filled with masses of heavy ice, which though they had been pre- 

 viously broken by the immense weight of the berg, were again formed into a compact body by its pressure. 

 The berg was drifting at the rate of about four knots, and by its force on the mass of ice, was pushing the ship 

 before her^ as it appeared, to inevitable destruction." 



" Feb. 2Ath. — The iceberg still in sight, but driving away fast to the N. E." 



" Feb. 25th. — The iceberg that so lately threatened our destruction, had driven completely out of sight 

 to the N. E. from us." — j1 relic Regions — voyage to Davis' Strait, by Dorea Duncan, Master of the Ship Dundee, 

 1826-7. 



Now then whence, unless from the difference of specific gravity due sea water of different degrees of salt- 

 ness, can we derive a locomotive power with force sufficient to give such tremendous masses of ice such a 

 velocity .'' 



What is the temperature of this undercurrent? Be that what it may, it is probably above the freezing point of 

 sea water. Suppose it to be at 36°. Break through the ice in the northern seas, and the temperature of the water 

 is always 28°. At least Lieut. De Haven so found it in his long imprisonment, and it may be supposed that 

 as it was with him, so it generally is. Assuming then the water of the surface current which runs out with the 

 ice to be all at 28°, we observe that it is not unreasonable to suppose that the water of the under current, in- 

 asmuch as it comes from the South, and therefore from warmer latitudes, is probably not so cold, and if it be 



