Evidence in relation to the Antarctic 

 Continent. Drift of the ice. 



ANTARCTIC CRUISE. 



The Yiucennes sails for the 

 north. 



149 



Much inquiry and a strong desire has been 

 evinced by geologists, to ascertain the extent to 

 which these ice-islands travel, the boulders and 

 masses of earth they transport, and the direction 

 they take. 



From my own observations, and the information 

 I have collected, there appears a great difference 

 in the movements of these vast masses ; in some 

 years, great numbers of them have floated north 

 from the Antarctic Circle, and even at times ob- 

 structed the navigation about the capes. The 

 year 1832 was remarkable in this respect; many 

 vessels bound round Cape Horn from the Pacific, 

 were obliged to put back to Chili, in consequence 

 of the dangers arising from ice; while, during the 

 preceding and following years, little or none was 

 seen : this would lead to the belief, that great 

 changes must take place in the higher latitudes, 

 or the pre valence of some cause to detach the 

 ice-islands from the barrier in such great quantities 

 as to cover almost the entire section of the ocean 

 south of the latitude 50 S. Taking the early part 

 of the (southern) spring, as the time of separation, 

 we are enabled to make some estimate of the 

 velocity with which they move : many masters of 

 vessels have met them some six or seven hundred 

 miles from the barrier, from sixty to eighty days 

 after this period, which will give a near approxi- 

 mation to our results heretofore stated. 



The season of 1839 and 1840 was considered as 

 an open one, from the large masses of ice that 

 were met with in a low latitude, by vessels that 

 arrived from Europe at Sydney : many of them 

 were seen as far north as latitude 42 S. 



The causes that prevail to detach and carry 

 them north are difficult to assign. I have referred 

 to the most probable ones that would detach them 

 from the parent mass in their formation. Our 

 frequent trials of currents, as has been stated, did 

 not give us the assurance that any existed; but 

 there is little doubt in my mind that they do pre- 

 vail. I should not, however, look to a surface 

 current as being the motive power that carries 

 these immense masses at the rate they move ; 

 comparatively speaking, their great bulk is below 

 the influence of any surface current, and the rapid 

 drift of these masses by winds is still more impro- 

 bable ; therefore I conceive we must look to an 

 under current as their great propeller. In one 

 trial of the deep-sea thermometer, we found the 

 temperature beneath four degrees warmer than 

 the surface. Off Cape Horn, the under tempera- 

 ture was found as cold as among the ice itself ; 

 repeated experiments have shown the same to 

 occur in the arctic regions. From this I would 

 draw the conclusion that changes are going on, 

 and it appears to me to be very reasonable to sup- 

 pose, that at periods, currents to and from the 

 poles should at times exist ; it is true, we most 

 generally find the latter to prevail, as far as our 

 knowledge of facts extends, but we have not suffi- 

 cient information yet to decide that there is not a 

 reflow towards the pole; the very circumstance of 

 the current setting from the higher latitudes, 

 would seem a good argument that there must be 

 some counter-current to maintain the level of the 

 waters. These masses, then, are most probably 

 carried away in the seasons when the polar streams 

 are the strongest, and are borne along by them at 

 the velocity with which they move : that these do 



not occur annually may be inferred from the ab- 

 sence of ice-islands in the lower latitudes ; and 

 that it is not from the scarcity of them, those who 

 shared the dangers of the antarctic cruise, will, 

 I have little doubt, be ready to testify ; for, al- 

 though great numbers of them studded the ocean 

 that year, yet the narrative shows that vast num- 

 bers of them were left. 



The specific gravity of the ice varies very much, 

 as might naturally be expected; for while some of 

 it is porous and of a snowy texture, other islands 

 are in great part composed of a compact blue flinty 

 ice. This difference is occasioned by the latter 

 becoming saturated with water, which afterwards 

 freezes. 



On the ice there was usually a covering of about 

 two feet of snow, which in places had upon it a 

 crust of ice not strong enough to bear the weight 

 of a man. Those ice-islands, which after having 

 been once seen, were again passed through imme- 

 diately after a gale, were observed to be changed 

 in appearance; but though for forty-eight hours a 

 severe storm had been experienced, they had not 

 undergone so great a transformation as not to be 

 recognized. They also appeared to have shifted 

 their position with regard to one another, their 

 former bias and trendings being broken up. 



During our stay on the icy coast, I saw nothing 

 of what is termed pack-ice, that is, pieces forced 

 one upon the other by the action of the sea or 

 currents. 



On the 21st, the weather became unsettled, with 

 light westerly winds, and we made but little pro- 

 gress to the westward. The barrier, at 6 P.M., 

 was seen trending to the westward. In conse- 

 quence of indications that threatened bad weather, 

 I deemed it useless risk to remain uvthe proximity 

 of so many ice-islands; and a strong breeze, with 

 squally weather, having already set in, I took ad- 

 vantage of it, feeling satisfied that our further 

 continuance in this icy region would not only be 

 attended with peril to the ship, but would cause a 

 waste of the time which was demanded by my 

 other duties ; and having nearly three thousand 

 miles to sail to our next port (Bay of Islands), I 

 made up my mind to turn the head of the vessel 

 northward. 



I therefore had the officers and crew called aft, 

 thanked them all for their exertions and good 

 conduct during the trying scenes they had gone 

 through, congratulated them on the success that 

 had attended us, and informed them that I had 

 determined to bear up and return north. 



Having only twenty-five days' full allowance of 

 water, I ordered its issue to be reduced to half 

 allowance. 



I have seldom seen so many happy faces, or such 

 rejoicings, as the announcement of my intention to 

 return produced. But although the crew were 

 delighted at the termination of this dangerous 

 cruise, not a word of impatience or discontent had 

 been heard during its continuance. Neither had 

 there been occasion for punishment; and 1 could 

 not but be thankful to have been enabled to con- 

 duct the ship through so difficult and dangerous a 

 navigation without a single accident, with a crew 

 in as good, if not in better condition than when we 

 first reached the icy barrier. For myself, I indeed 

 felt worse for the fatigues and anxieties I had un- 

 dergone; but I was able to attend to all my duties, 



