ty-six feet. From thence again there is
a decrease towards, the north, the elevation at the Spurn Point being
from nineteen to twenty feet, and at Flamborough Head and the Yorkshire
coast from fourteen to sixteen feet.[381]

At Milford Haven in Pembrokeshire, at the mouth of the Bristol Channel,
the tides rise thirty-six feet; and at King-Road near Bristol, forty-two
feet. At Chepstow on the Wye, a small river which opens into the estuary
of the Severn, they reach fifty feet, and sometimes sixty-nine, and even
seventy-two feet. A current which sets in on the French coast, to the
west of Cape La Hague, becomes pent up by Guernsey, Jersey, and other
islands, till the rise of the tide is from twenty to forty-five feet,
which last height it attains at Jersey, and at St. Malo, a seaport of
Brittany. The tides in the Basin of Mines, at the head of the Bay of
Fundy in Nova Scotia, rise to the height of seventy feet.

There are, however, some coasts where the tides seem to offer an
exception to the rule above mentioned; for while there is scarcely any
rise in the estuary of the Plata in S. America, there is an extremely
high tide on the open coast of Patagonia, farther to the south. Yet even
in this region the tides reach their greatest elevation (about fifty
feet) in the Straits of Magellan, and so far at least they conform to
the general rule.[382]

_Currents._--The most extensive and best determined system of currents,
is that which has its source in the Indian Ocean under the influence of
the trade winds; and which, after doubling the Cape of Good Hope,
inclines to the northward, along the western coast of Africa, then
across the Atlantic, near the equator, where it is called the equatorial
current, and is lost in the Caribbean Sea, yet seems to be again revived
in the current which issues from the Gulf of Mexico. From thence it
flows rapidly through the Straits of Bahama, taking the name of the Gulf
Stream, and passing in a northeasterly direction, by the Banks of
Newfoundland, towards the Azores.

We learn from the posthumous work of Rennell on this subject, that the
Lagullas current, so called from the cape and bank of that name, is
formed by the junction of two streams, flowing from the Indian Ocean;
the one from the channel of Mozambique, down the southeast coast of
Africa; the other from the ocean at large. The collective stream is from
ninety to one hundred miles in breadth, and runs at the rate of from two
and a