ents.[2]

[Footnote 2. In the old Portuguese maps and voyages, this part of
the Atlantic is called _Mar de Sargasso_, or the _Sea of Cresses_;
Sargasso signifying water-cresses, which these weeds which spread over
the sea nearly resemble.--Harris.]

Nothing is more difficult than to account for the motion and course
of currents in the ocean, which, in some places, run for six months
in one direction, and six in another, while in other places they run
always one way. There are instances also where they run one way for
a day or two after full moon, and then run strongly in the opposite
direction till next full moon. Seamen also observe, that in places
where the trade-winds blow, the currents are generally influenced by
them, moving the same way with the winds, but not with equal force
in all places; neither are they so discernible in the wide ocean,
but chiefly about islands, where their effects are more or less felt
according as they are influenced by being more or less in the way
of the trade-winds. It would be of great service to navigation if
sensible men would take notice of these currents, and enquire into the
reason of their appearances. In old books of voyages we find many more
wonders than in those of later date, not because the course of nature
is at all changed, but because nature was not then so well understood.
A thousand things were prodigious a century ago, which are not now at
all strange. Thus the storms at the Cape of Good Hope, which make so
great a figure in the histories of the Portuguese discoveries, are now
known to have been merely the effect of endeavouring to double that
Cape at a wrong season of the year.

In the East and West Indies, the natives are able to foretell
hurricanes and tornadoes, not from any superior skill, but by
observing certain signs which usually precede them. There is often so
little apparent connection between the sign and the event, that men
who value themselves on their wisdom are apt to slight such warnings
as impertinent and absurd. But they had better enquire diligently into
facts, and neither receive nor reject them too hastily. In the present
case, it is a clear matter of fact that the sea, in the latitude of
18 deg. N. between Africa and America, is frequently covered with weeds
to a great extent, and there is good reason for enquiry as to whence
these weeds come. In the first voyage made by the famous Columbus for
the discovery of the new world, he met with this