The Great Storm of March 11-U, 1888. 45 



destructive violence between Hatteras and Block Island, and 

 finally to disturb the weather of the entire North Atlantic north 

 of the 20th parallel. 



The great warm ocean current called the Gulf Stream has, to 

 most people, a more or less vague, mythical existence. The words 

 sound familiar, but the thing itself is only an abstract idea ; it 

 lacks reality, for want of any personal experience or knowledge of 

 its characteristic effects. To the navigator of the North Atlantic 

 it is a reality ; it has a concrete, definite existence ; it is an ele- 

 ment which enters into the calculations of his every-day life — 

 sometimes as a friend, to help him on his course, sometimes as an 

 enemy, to endanger, harass, and delay. Briefly, the warm waters 

 of the tropics are carried slowly and steadily westward by the 

 broad equatorial drift-current, and banked up in the Caribbean 

 Sea and Gulf of Mexico, there to constitute the head or source of 

 the Gulf Stream, by which the greater portion is drained off 

 through the straits of Florida in a comparatively narrow and 

 swiftly moving stream. This great movement goes on unceasingly, 

 subject, however, to certain variations which the changing seasons 

 bring with them. As the sun advances northward in the spring, 

 the southeast trades creep up toward and across the equator, the 

 volume of that portion of the equatorial current which is diverted 

 to the northward of Cape San Roque is gradually increased, and 

 this increase is soon felt far to the westward, in the Yucatan and 

 Florida straits. Figures fail utterly to give even an approximate 

 idea of the amount of heat thus conveyed from the tropics to the 

 north temperate zone by the ceaseless pulsations of this mighty 

 engine of oceanic circulation. To put it in some tangible shape 

 for the mind to grasp, however, suppose we consider the amount 

 of energy, in the form of heat, that would be liberated were this 

 great volume of water reduced in temperature to the freezing 

 point. Suppose,, again, that we convert the number of heat-units 

 thus obtained into units of work, so many foot-pounds, and thence 

 ascertain the corresponding horse-power, in order to compare it 

 with something with which we are familiar. Considering only 

 the portion of the Gulf Stream that flows between Cape Florida 

 and the Great Bahama bank, we find from the latest and most 

 reliable data, collected by the U. S. Coast and Geodetic Survey, 

 that the area of cross section is 10.97 square miles (geographic or 

 sea miles, of 6,086 feet each) ; mean velocity, at this time of the 

 year, 1.305 miles per hour ; mean temperature, 71° F. These 



