356 Wyville Thomson— General Ocean Circulation. 
the Great Island and Alexander Land, discovered by Billings- 
hausen in 1821, Graham Land and Adelaide Island, discovered 
by Biscol in 1832, and Louis Philippe Land by D’Urville in 
1838, and at least one majestic modern volcanic range discovered 
by Ross in 1841 and 1842, stretching from Balleny Island to a 
latitude of 78°S., and rising to a height of 15,000 feet. It 
seems, so far as is at present known, that the whole of the 
antarctic land, low and high, as well as the ice-cap of which a 
portion of the continuous continent may consist, is bordered to 
some distance by a fringe of ice, which is bounded to seaward 
by a perpendicular ice-cliff, averaging 230 feet in height above 
the sea-level. Outside the cliff a floe, which attains near the 
barrier a thickness of about twenty feet, and in some places by 
piling a considerably greater thickness, extends northward in 
winter to a distance varying according to its position with 
reference to the southward trending branches of the equatorial 
current; and this floe is replaced in summer by a heavy drift- 
ing pack with scattered icebergs. Navigating the Antarctic 
ea in the southern summer, the only season when such navi- 
gation is possible, it has been the opinion of almost all explorers, 
that after forcing a passage through an outer belt of heavy 
pack and icebergs, moving as a rule to the northwestward, an 
thus fanning out from the ice-cliff in obedience to the prevailing 
southeasterly winds, a band of comparatively clear water is to 
be found within. 
Several considerations appear to me to be in favor of the 
view that the area round the South Pole is broken up and not 
continuous land. For example, if we look at a general ice- 
chart we find that the sea is comparatively free from icebergs, 
and that the deepest notches occur in the “Antarctic Continent’ 
at three points, each a little to the eastward of south of one of 
the great land masses. Opposite each of these notches a branch 
of the equatorial current is deflected southward by the land, 
and is almost merged in the great drift-current which sweeps 
round the world in the Southern Sea before the westerly antl- 
