160 Association of American Geologists and Naturalists. 



up the sloping sides to the height of eighty or one hundred feet, recoil- 

 ing in vast sheets resembling cataracts ; and where the face of the 

 berg was perpendicular, the surf broke against it as if it had been a 

 wall of rock, with tremendous force, and a booming roar like that of 

 distant heavy thunder. There appeared to have been a recent over- 

 turn of the berg, inasmuch as the water for a mile's distance from it 

 was full of fragments, some of them sufficiently large to endanger a 

 vessel. One of the most remarkable phenomena observed by Mr. C, 

 was the almost incredibly rapid revolution of this huge body on its 

 vertical axis, in consequence of which, it did not present the same 

 aspect for two minutes together. One moment it was a pyramid, the 

 next barn-shaped, and in another a glittering pile of peaks and serrated 

 crests, or battlements, like those of some ancient castellated citadel, 

 was exhibited. Scarcely was there time to sketch the rudest outline of 

 one configuration, ere it gave place to another totally dissimilar. This 

 melting away of the various figures, could be compared to nothing 

 better than the sudden and fanciful changes we see in turning a kaleido- 

 scope. Mr. Couthouy here exhibited to the Association a series of 

 sketches taken at the time as illustrative of the variety of form spoken 

 of. The following statement of the temperature of the air and ocean 

 at various distances from the berg, was given as evidence of the great 

 extent to which they were affected by its presence, and the influence 

 which, as before mentioned, this circumstance exerted on the retard- 

 ation of the dissolution of similar masses : 



Noon. 2 p.m. 3 p.m. 3 30 p.m. 4p.m. 4 30 p.m. 5 p.m. 5 30p.m. 



Air, 54° 53° 50° 46° 42° 37° 35° 37° 



Water, 50° 50° 48° 44° 43° 36° 36° 40° 



Distance of berg, 33' 19' (visible,) 12' 8' 4J' 1' 3' 6' 



When nearest the iceberg, (which was within a short half mile,) the 

 water was at a little below 34° Fahr., and the air at 35°. After pass- 

 ing the island, when about two miles to leeward, a smart fall of hail 

 was experienced, which lasted about ten minutes. By this statement 

 it appears, that the water three miles to leeward of the island was 7° 

 Fahr. colder than that four and a half miles to windward, and at 

 six miles, 3° colder than at four and a half and 4° colder than at eight 

 miles to windward, owing probably to a surface current carrying the 

 cold water from it in the direction the wind was blowing. The latitude 

 of this ice island was 53° 20' S., and its longitude 104° 50' W., making 

 its distance from Terra del Fuego, the nearest eastern land, one thou- 

 sand four hundred and fifty miles, and one thousand from St. Peter's 

 and Alexander's Islands, the proximate southern land from which it 

 could have been detached. From its great magnitude, it was the opin- 

 ion of Mr. C. that should this berg have been driven by the westerly 



