The universal geography : earth and its inhabitants

GULF STREAM—TEMPERATURE. 8better understood than that of the currents. The great tidal flow setting northwards,and reaching the opposite shores of the two hemispheres at the same time,is divided into three distinct streams on reaching the south-western shores of theBritish Isles. The main stream continues its northern course along the west coastof Ireland, while the two others enter the St. George's and English Channels.But after flowing round the west and north coasts of Ireland the first streampasses through the North Channel between Great Britain and Ireland, and theremeets the second on its way from the south. The main stream, after making thecircuit of Scotland, flows southwards along the east coast of England until itmeets the third from the English Channel about the Straits of Dover. At thesame time these streams are constantly modified according to the position of sunand moon, the force and direction of the winds, the endless varieties of theatmosphere, so that mean results alone can be given.*Gulf Stream.— Temperature.Like the tides, the main currents of the North-east Atlantic flow from thesouth and south-west. To a depth of over 500 fathoms the surface waters onthe whole flow from south-west to north-east, and from south to north, fromthe Bermudas and Azores to the British Isles, Iceland, Scandinavia, andSpitzbergen. This is placed beyond all doubt by the tropical plants andarticles of human industry, bearing the marks of theirshores of Northern Europe and the polar islands.origin, strewn along theBut it is difficult to say to whatextent the Gulf Stream, escaping through Florida Channel from the Gulf ofMexico, is thus continued in the vast current traversing the entire breadth of theNorth Atlantic. Carpenter,! Findlay, and other physicists rightly regard thiscurrent as the result of a general displacement occasioned by the tepid waters ofthe torrid zone setting in towards the cold waters of the arctic seas. In fact,Florida Channel is far too narrow to give egress to a stream spreading for a spaceof at least 2,400,000 square miles between Scandinavia, Iceland, and Newfoundland,and reaching a greater depth than 830 fathoms below the surface. The flowof the Gulf Stream at the Bahamas is variously estimated at from 500,000 $ to3,000,000,000 § cubic yards per second by writers who have a theory to support.But the approximate calculations of others give a nominal volume of about52,000,000 cubic yards, which would take no less than ten years to fill the wholespace at present occupied by the tepid waters. Besides, the hydrographers whohave studied the Bermuda seas have ascertained that off the United States coastthe Gulf Stream branches into a number of smaller currents, separated from eachother by masses of colder water, and all gradually merging in the main current ofthe Atlantic.* The tidal systems are described in vol. iv. p. 7.t Lecture at the Royal Institution, Nature, March 10th, 1870.X James Croll, Philosophical Magazine, February, 1870.§ Findlay, Journal of the Geographical Society, 1853; Proceedings, 1869.