36 



WAVE DIMENSIONS 



former is the more reliable of the two, for it is difficult to take exact 

 measurements of waves at sea. 



O 200 400 600 800 IOOO 1200 1400 1600 1 800 



LENGTH ID. FEET 



Figuek 5. — Graphical presentation of the theoretical relationship between wave 

 lengths, velocities, and periods in deep water. 



Table 17. — The lengths of waves (ns observed and as computed from the observed 

 periods) and the wave periods (as observed and as computed from the observed 

 lengths) in different parts of the oceans 



[Adapted from Kriimmel and from Sverdrup, Johnson, and Fleming) 



Incidentally, 26 seconds (reported from the south coast of England) 

 is the longest period yet recorded in print for any wave, though we 

 are informed that waves with periods as long as 30 seconds have been 

 observed at Long Beach, Calif. And velocities of about 79 knots and 

 of about 91 knots that correspond, respectively, to the periods just 

 quoted are the highest that have ever been reported for wind waves 

 at sea. But even these are insignificant as compared with the speeds 

 at which the waves travel from severe earthquakes, such as that of 

 1868, when the resultant waves in the Pacific had estimated velocities 

 of 300 to 400 knots; or the wave from the Straits of Sunda, or 

 Krakatoa quake of 1883, which must have advanced at a rate nearly 



