148 



Formation and size of icebergs. 

 Movement of ice along the coast. 



ANTARCTIC CRUISE. 



Evidence In relation to the Antarctic 

 Continent. 



must pass to the northward during the next season, 

 partly influenced by the current, and partly scat- 

 tered by the prevailing winds, until they reach the 

 sixtieth degree of latitude, when they encounter 

 the easterly and north-easterly streams that are 

 known to prevail, which carry them rapidly to the 

 north. 



Our data for their actual drift, though not alto- 

 gether positive, are probably the best than can be 

 had, and will go far towards ascertaining the 

 velocity of their progress to lower latitudes ; our 

 observations also furnish some estimate of the time 

 in which they are formed. On our way south, we 

 did not fall in with ice-islands until we reached 

 latitude 61 S. The Peacock was the first to re- 

 turn, and nearly upon the track by which we had 

 gone south ; the last seen by her was in 55 S. 

 The Vincennes, on her return fifty days later, saw 

 them in 51 S. The Porpoise, about the same 

 time, in 53 S. The observation in the Vincennes 

 gives a distance of ten degrees of latitude, or six 

 hundred miles to be passed over in fifty days, 

 which would give about half a mile an hour ; or, 

 taking the Peacock's observations, a more rapid 

 rate would be given, nearly three-fourths of a mile. 

 Many icebergs were met in the latitude of 42 S., 

 by outward-bound ships to Sydney, in the month of 

 November ; these, I learned, were much worn, and 

 showed lofty pinnacles, exhibiting no appearance of 

 having ever been of a tabular form. These no 

 doubt are such as were detached during a former 

 season, and being disengaged from the barrier, 

 would be naturally, early the next season, drifted 

 by the easterly current as well as* the westerly 

 wind, and would pursue the direction they give 

 them. They would therefore be driven to the 

 north-east as far as the south-east winds prevail, 

 and when these veer to the westward would receive 

 an easterly direction. It is where these winds pre- 

 vail that they are most frequently found by the 

 outward-bound vessels, between the latitudes of 

 40 and 50 S. 



Respecting the period of time required for the 

 formation of these ice-islands, much light cannot 

 be expected to be thrown on the subject ; but the 

 few facts derived from observations lead to some 

 conclusions. Many of them were measured, and 

 their altitude found to be from fifty to two hundred 

 and fifty feet ; eighty distinct stratifications were 

 counted in some of the highest, and in the smallest 

 thirty, which appeared to average a little more 

 than two feet in thickness. Supposing the average 

 fall of snow in these high latitudes to be an inch a 

 day, or thirty feet a year, the largest icebergs would 

 take more than thirty years to form. They were 

 seen by us in all the stages of their growth, and all 

 bore unequivocal marks of the same origin. The 

 distance from the land at which they were forming, 

 fully satisfied me that their fresh water could only 

 be derived from the snows, &c. 



The movement of the ice along the coast is 

 entirely to the westward, and all the large ranges 

 of ice-islands and bergs were found in that di- 

 rection, while the eastern portion was compara- 

 tively free from it. A difference was found in the 

 position of the floe-ice by the different vessels, 

 caused rather by the wind than by the tide. When 

 the Vincennes and Porpoise passed the opening by 

 which the Peacock entered, it was found closed, 

 although only twenty-four hours had elapsed. It 



has been seen that the ice had much movement 

 during the time the Peacock was beset by it, and 

 the bay was all but closed when she effected her 

 escape. Another instance occurred, where the 

 Porpoise, in about the longitude of 130 E., found 

 the impracticable barrier a few miles further south 

 than the Vincennes did six or seven days after ; 

 but this fact is not to be received as warranting 

 any general conclusion, on account of the occur- 

 rence of south-east gales during the intermediate 

 time. The trials for currents have, for the most 

 part, shown none to exist. The Porpoise, it is 

 true, experienced some, but these were generally 

 after a gale. If currents do exist, their tendency 

 is westward, which I think the drift of the ice 

 would clearly prove. The diffei'ence between the 

 astronomic positions and those given by dead- 

 reckonings, was of no avail here as a test*, for the 

 courses of the vessels among the ice were so tor- 

 tuous, that the latter could not be depended upon. 



The winds which prevail from the south-west to 

 the south-east occasionally bring clear weather, 

 interrupted by flurries of snow ; the north wind is 

 light, and brings thick fogs, attended by a rise of 

 temperature. Extremes of weather are experienced 

 in rapid succession, and it is truly a fickle climate. 

 The evidence that an extensive continent lies 

 within the icy barrier, must have appeared in the 

 account of my proceedings, but will be, I think, 

 more forcibly exhibited by a comparison with the 

 aspect of other lands in the same southern parallel. 

 Palmer's Land, for instance, which is in like manner 

 invested with ice, is so at certain seasons of the year 

 only, while at others it is quite clear, because strong 

 currents prevail there, which sweep the ice off to 

 the north-east. Along the Antarctic Continent for 

 the whole distance explored, which is upwai'ds of 

 fifteen hundred miles, no open strait is found. The 

 coast, where the ice permitted approach, was found 

 enveloped with a perpendicular barrier, in some 

 cases unbroken for fifty miles. If there was only a 

 chain of islands, the outline of the ice would un- 

 doubtedly be of another form ; and it is scarcely to 

 be conceived that so long a chain could extend 

 so nearly in the same parallel of latitude. The 

 land has none of the abruptness of termination 

 that the islands of high southern latitudes ex- 

 hibit; and 1 am satisfied that it exists in one un- 

 interrupted line of coast, from Ringgold's Knoll, 

 in the east, to Enderby's Land, in the west ; that 

 the coast (at longitude 95 E.) trends to the north, 

 and this will account for the icy barrier existing, 

 with little alteration, where it was seen by Cook 

 in 1773. The vast number of ice-islands conclu- 

 sively points out that there is some extensive 

 nucleus which retains them in their position; for 

 I can see no reason why the ice should not i>e dis- 

 engaged from islands, if they were such, as hap- 

 pens in all other cases in like latitudes. The for- 

 mation of the coast is different from what would 

 probably be found near islands, soundings being 

 obtained in comparatively shoal water ; and the 

 colour of the water also indicates that it is not like 

 other southern lands, abrupt and precipitous. This 

 cause is sufficient to retain the huge masses of ice, 

 by their being attached by their lower surfaces 

 instead of their sides only. 



* The fact of there being no northerly current along tin's 

 extended line of coast, is a strong proof in my mind of its 

 being a continent, instead of a range of islands. 



