142 WATERSPOUTS. [SECT. xv. 



proach of a hurricane, so the laws of the storm's motion 

 afford to the seaman the knowledge to guide him in avoiding 

 it. In the northern temperate zone, if the gale begins from 

 the S.E. and veers by S. to W., the ship should steer to the 

 S.E. ; but, if the gale begins from the N.E., and changes 

 through K to N.W., the vessel should go to the N.W. In 

 the northern part of the torrid zone, if the storm begin from 

 the N.E., and veer through E. to S.E., the ship should steer 

 to the N.E. ; but, if it begin from the KW., and veer by W. 

 to S.W., the ship should steer to the S.W., because she is in 

 the south-western side of the storm. Since the laws of 

 storms are reversed in the southern hemisphere, the rules 

 for steering vessels are necessarily reversed also. A heavy 

 swell is peculiarly characteristic of these storms. In the 

 open sea the swell often extends many leagues beyond the 

 range of the gale which produced it. 



Waterspouts are occasioned by small whirlwinds, which 

 always have their origin at a great distance from that part 

 of the sea from which the spout begins to rise, where it is 

 generally calm. The whirl of the air begins in the clouds, 

 and, extending downward to the sea, causes the water to 

 ascend in a spiral by the impulse of the centrifugal force. 

 When waterspouts have a progressive motion, the vortex of 

 air in the cloud above must move with the same velocity, 

 otherwise the spouts break, which frequently happens. 



