406 THE ANTARCTIC MANUAL. 
In some places we sailed for more than 50 miles together, along a 
straight and perpendicular wall, from 150 to 200 feet in height, with 
the land behind it. The icebergs found along the coast afloat were from 
a quarter of a mile to five miles in length; their separation from the 
land may be effected by severe frost rending them asunder, after which 
the violent and frequent storms may be considered a sufficient cause to 
INCLINED ICEBERG. 
overcome the attraction which holds them to the parent mass. In their 
next stage they exhibit the process of decay, being found 50 or 60 
miles from the land, and for the most part with their surfaces inclined 
at a considerable angle to the horizon. This is caused by a change in 
the position of the centre of gravity, arising from the abrading action 
of the waves. 
By our observations on the temperature of the sea, it is evident that 
these ice-islands can be little changed by the melting process before they 
reach the latitude of 60°. The temperature of the sea (as observed by 
the vessels going to and returning from the south) showed but little 
change above this latitude, and no doubt it was at its maximum, as it 
was then the height of the summer season. 
During their drift to the northward, reaching lower latitudes, and as 
ICEBERG. 
their distance from the land increases, they are found in all stages of 
decay ; some forming obelisks; others towers and Gothic arches; and 
all more or less perforated ; some exhibit lofty columns, with a natural 
bridge resting on them, of a lightness and beauty inconceivable in any 
other material. The annexed wood-cut and the tail-pieces of the chapters 
are sketches of some of them. 
