A warm water current
that travels along the east coast of the United States from near the equator
to North Carolina
where it then flows northeast to the coasts of Great Britain
. The Gulf Stream brings warmer water to the coasts of these northern regions keeping their winter temperatures much warmer
than they actually should be.
There is a river in the ocean. In the severest droughts it never fails, and in the mightiest floods it never overflows. Its banks and its bottom are of cold water, while its current is of warm. The Gulf of Mexico is its fountain, and its mouth is in the Artic Seas. It is the Gulf Stream. There is in the world no other such majestic flow of waters. Its current is more rapid than the Mississippi or the Amazon.
Its waters, as far out from the Gulf as the Carolina coasts, are of an indigo blue. They are so distinctly marked, that their line of junction with the common sea-water may be traced by an eye. Often one half of the vessel may be perceived floating in the Gulf Stream water, while the other half is in common water of the sea, so sharp is the line, and such a want of affinity between those waters, and the reluctance, on the part of those of the Gulf Stream to mingle with the common water of the sea.
Matthew Fontaine Maury
from The Physical Geography of the Sea