16 
progresses for centuries under no natural condition of dimi- 
nution, but by the ofl'shoot of bergs, and their transference 
southwards by ocean currents. Local circumstances of thaw 
in the brief polar summer, though resulting in evaporation, 
yet only cause local rains, haze, or snow, rendering ice sur- 
faces mora glassy, reflective of solar rays, and impervious to 
wasting influences. 
The Arctic voyager, Dr. Kane, remarks that " the Alpine 
glaciers have engrossed tho Held of scientific dissertation 
somewhat unduly. Those which crowd the western coast of 
Greenland have perhaps a higher interest, growing up as 
they do in a climate which in independent of altitude, besides 
being altogether superior in magnitude of scale." He 
defines the glacier to be " a mass of ice, derived from the 
atmosphere, sometimes abutting on the sea:" and he thus 
describes the Great, or Humboldt glacier. " This line of clitf 
rose in a solid glassy wall 300 feet above the water level, with 
an unknown unfathomable depth beneath it, and its curved 
face vanished into unknown apace. The interior with which 
it communicated was an unsurveyed mer de glace, an ice 
ocean to the eye, of boundless dimensions. Greenland is in 
mass continental, having a length of more than 1,200 miles, 
not materially less than Australia from its north to its 
south cape. Imagine now the centre of such a continent 
occupied through nearly its whole extent by a deep 
unbroken sea of ice, that gathers perennial increase from 
the watershed of vast snow-covered mountains, and all the 
precipitation of the atmosphere upon its own surface. . . . 
You walked as over a terrestrial surface, met by every 
diversity of configuration, valleys, gorges, hills, plains, and 
precipices/' Again, "the mer de glace -which occupies tho 
central plateau of Northumberland, is completely isolated 
and washed by the sea, and is necessarily dependent for its 
increments upon the atmospheric precipitation of a limited 
surface, yet it sustains in its discharge, no less than seven 
glaciers, one of which is half a mile in diameter by 200 feet 
in depth,— a startling instance of the redundance of Arctic 
ice growth." " The circumstance of the glaciers' offcasts 
being so numerous seems to indicate a continuously pro- 
truding influence," doubtless from the superincumbent 
pressure of ever-increasing accumulation. Captain Sherard 
Osborne described the Antarctic ice barrier to be "the 
seaward edge of an enormous continental glacier." How 
can vapour precipitated and locally congealed upon accumu- 
lated piles of drifted ice Hoes, attain to the aspect of a 
continent ? Dr. Maury observes, " To evaporate water 
