THE ENGINE OF THE AIR 159 



toward the center, but vary in different sections of the cyclonic 

 circle. In front of the storm the winds tend to blow directly 

 across the path, and in the rear to follow a more immediate 

 line toward the center. 



A consistent feature is the variation of intensity between the 

 right- and left-hand sides of the hurricane. The right side, 

 where the winds blow from the rear forward and around the 

 front, has the added force of the speed of the storm as a 

 whole, which may be considerably more than ten miles per 

 hour. Conversely the winds heading toward the rear on the 

 left side are partly cancelled out by just this forward speed of 

 the whole storm, and are therefore less severe. The forward 

 right quadrant of the storm is where the real business of 

 wind and rain goes on, where winds can rise to 150 miles per 

 hour and rains amount to a terrific cloudburst. Some hurri- 

 canes have precipitated as much as two or three feet of rain- 

 fall in their passage, or the equivalent of the annual rainfall 

 of Paris or London. 



This terrific precipitation is a part of the wind engine that 

 furnishes the energy of the cyclone by the release of heat. 

 Nothing can better describe the workings of a hurricane than 

 the words of I. M. Cline of the U. S. Weather Bureau, who 

 has been a pioneer in the study of tropical storms. This is 

 how the engine works: ''The winds in the rear right-hand 

 quadrant blow in the same general direction as that in which 

 the cyclone center is traveling and continue to do so during 

 the life of the storm. These winds with velocities of 40 to 

 100 miles an hour or more, converge upon the winds of the 

 front right-hand quadrant, which have a variable inclination 

 towards the center but which, within a hundred miles of the 

 center, blow nearly at right angles to the line of advance. The 

 winds in this front right quadrant blow intermittently in sud- 

 den local powerful gusts which appear to have a marked 

 vertical component upwards. 



'Trecipitation occurs mainly in this front right-hand quad- 



