6 



being clue solely to mass transport. This distance (1-5 in the figure), 

 in true magnitude, was divided by the wave period to obtain the 

 velocity of mass transport. The direction of mass transport was 

 determined by reference to the direction of travel of the wave, trans- 

 port in the direction of wave travel being designated as positive. 



Surface mass transport. — The existence and magnitude of surface 

 mass transport was determined by a floating cork ball Iji inches in 

 diameter. The time for travel of the ball over a measured course of 

 ten feet was observed and the velocity of surface mass transport 



obtamed as — • 



Percentage of wave height above still water level. — ^Measured values of 

 the proportion of wave height above the still water level were ob- 

 tained from wave profile photographs. The proportion is expressed 

 as the ratio of the height of the wave crest above the still water level 

 to the wave height. For each characteristic wave the percentage 

 wave height above still water level was measured at three positions 

 in the wave tank, 12, 24, and 37 feet from the wave generator. 



5. DEEP-WATER WAVES 



The basic data for the deep-water waves studied are given in 

 table 1. 



The ratio A/X is employed as a criterion of wave type — ratios 

 greater than about 0.03 corresponding to storm waves — and as a 

 parameter in the computation of wave characteristics by the Stokes- 

 Levi-Civita equations. 



/d \ 



Table 1. — Basic data — Deep-water waves yj^O.B ) 



1 



Run 



.\verage. 



2 

 h„. 



Sec. 

 0.850 



003 



'. p. s. 

 4.39 

 6.10 

 4.40 

 5.00 

 4.42 

 4.89 

 4.81 

 4.23 

 4.31 

 5.07 

 4.33 

 6.05 



Feet 

 3.89 

 5.14 

 3.83 

 4.87 

 3.79 

 4.76 

 4.75 

 3.57 

 3.55 

 5.02 

 3.60 

 4.92 



Feet 



3 



2.5 



2.5 



3 



3 



2.5 



2.5 



3 



3 



2.5 



2.5 



7 

 dlL„ 



0.771 

 .584 

 .653 

 .513 

 .792 

 .630 

 .527 

 .706 

 .845 

 .598 

 .695 

 .509 



ha,.IL„ 



0.0707 

 .0460 

 .0600 

 .0423 

 .0638 

 .0460 

 .0398 

 .0705 

 .0552 

 .0321 

 .0464 

 .0601 



C,„T„ 



Feet 

 3.73 

 5.17 

 3.79 

 4.93 

 3.75 

 4.74 

 4.65 

 3.58 

 3.63 

 5.05 

 3.65 

 4.99 



10 



CmT,n-Ln 



Percent 

 -4.4 

 -0.5 

 -1.0 

 +1.2 

 -1.1 

 -0.4 

 -2.1 

 +0.3 

 +2.2 

 +0.6 

 +1.4 

 +1.4 



-0.20 



The values listed in column 10, table 1, are of interest as showing 

 the accuracy of measurement. For any type of wave motion the 

 product of wave velocity and wave period is equal to the wave length. 



