AND OTHER WATER WAVES 111 



cordant are the results from the data of Desbois, 

 of Paris, and of Antoine, when recalculated by 

 the modern reduction -factor of wind velocity. On 

 an average the velocity of the wind in statute miles 

 per hour was found to be 2.05 times the height of 

 the wave in feet. Thus the average height of 

 the waves in a whole gale, Beaufort's force 9, 

 wind velocity 44 s.m.p.h., is : 



44 -r- 2-05 = 21-5 feet. 



As already explained, this average would be 

 exceeded when the wind had full opportunity to 

 do its work. 



The Relation between the Velocity of the Wind 

 and the Velocity of the Waves 



The greatest average length of storm -waves on 

 any one day recorded in the preceding pages is 

 that observed by Lieutenant Paris, viz., 771 feet, 

 which corresponds to a wave velocity of 43 statute 

 miles per hour. The average velocity of the wind, 

 as re-calculated from the conventional number in 

 Paris 's table, was 46 statute miles per hour. The 

 gale had lasted (or the ship, running before the 

 wind, had been in it ) for four days, or, say, 

 100 hours. During the first day of the gale the 

 wave-length was only 371 feet, corresponding to 



