THE WINDS OF THE OCEAN 45 



the atmosphere may rest undisturbed. But over 

 the main air currents lie possibilities of tremendous 

 aerial disturbances, as if Nature resented the even, 

 equable flow of the wind for any great length of time, 

 and must needs give it a tremendous shaking up just 

 to stimulate the circulation. And these catastrophic 

 events are known, according to their locality, as 

 hurricanes, cyclones or typhoons, or, in minor cases, 

 tornadoes or whirlwinds. But whatever their local 

 appellation, or wherever they take place, the principle 

 of them remains the same, viz. a more or less whirling 

 motion against the apparent passage of the sun, or in the 

 opposite direction to the movements of the hands of a 

 clock in the northern hemisphere, and with them in 

 the southern, while the whole whirling area of wind is 

 borne onward in a given direction, much as the wheel 

 revolves upon its axis, yet goes forward withal. 



But of these violent disturbances more presently, 

 and particularly in their turn. The place of honour 

 in the consideration of ocean winds must, I think, 

 always be given to the Trade Winds of the Atlantic, 

 not only for their important bearing upon the trade of 

 the world in the days that have gone, but their wonder- 

 ful influence upon the health of the countries that 

 dominate the rest of the world. Let it be remembered 

 that there are in the Atlantic Ocean two great currents 

 of air in motion, or wind, one north of the equator, 

 between 30 N., and that imaginary central line, called 

 the North-East Trade Winds, and the other occupy- 

 ing a similar position south of the equator, known as 

 the South-East Trades. Their names signify the 

 direction from which they blow continually, with a 

 little variation, it is true, according to the time of the 



