76 PILTYSICAL GEOGRAPHY OF THE SEA. 
bergen, immense glaciers frequently fill the valleys that open on 
the sea, descend even beyond the water’s edge, and, as they 
move along, their overhanging masses separate from their base 
and plunge into the deep with a crash louder than thunder. 
The icebergs that drift about the, Arctic seas, and are annually 
conveyed by the currents into lower latitudes, are formed in 
this manner. Huge blocks of granite, detached by atmo- 
spherical vicissitudes from the higher mountains and precipitated 
on the surface of the glaciers, frequently float on the broad back 
of an iceberg far away from the spot where they seemed rooted 
for eternity. As their crystal support melts away in its progress 
to warmer climes, these rocky fragments, which have been 
appropriately named erratic blocks, fall to the bottom of the sea 
hundreds or even thousands of miles from the starting point of 
their journey. Thus the great bank of Newfoundland is covered 
with stones from distant Greenland, raised high in the air by 
volcanic power myriads of years ago, and now condemned to an 
equally long repose below the surface of ocean. When will 
they rise again above the waters, and what further changes will 
they have to undergo ere their compacted atoms resolve them- 
selves into dust and assume new forms? But, however remote 
their dissolution, it will inevitably come, for Time is all-powerful, 
and has an eternity to work out his changes. 
The large blocks of stone that so wonderfully migrate on the 
wandering iceberg form but a small and insignificant portion of 
the terrestrial spoils which are transported to ocean by the 
returning waters. Every river is more or less laden with 
earthy particles which its current carries onwards to the sea 
and deposits at its mouth. In course of time their accumu- 
lation, as I have already mentioned, forms large tracts of fertile 
territory encroaching upon the maritime domains. 
T shall end with a few words on the influence of forests in 
attracting or retaining the atmospherical moisture, as it is a 
subject of great importance in the economy of nations, and 
shows us how much it is in the power of man to improve or to 
defeat the provisions of nature in his favour. 
Forests always cool the neighbouring atmosphere, for their 
foliage offers an immense warmth-radiating surface, so that the 
vapours readily condense above them and descend in frequent 
showers. At the same time their roots loosen the soil, and the 
