analyzed by the sieve method for quality control (described in Vol. I). 
The values reported here are the VA tube values, which are generally 
0.015 millimeter less than the sieve median. 
Tables 8 and 9 give the median grain-size results, including values 
at the beginning of the experiment (Table 8). The initial average 
median grain size by the VA tube method was 0.195 millimeter. 
A summary of the mean and range of the median grain sizes, and the 
number of samples within each profile zone are given in Table 10. In the 
foreshore zone, the mean of the median sizes increased as the finer sand 
preferentially eroded. The range of median size also increased. In the 
inshore zone, the mean of the median sizes increased slightly. In the 
offshore zone, the mean of the medians increased between 100 and 140 
hours and the range of medians gradually increased throughout the experi- 
ment. At the end of the experiment, the mean median was 0.25 millimeter 
in the foreshore zone, 0.22 millimeter in the inshore zone, and 0.21 
millimeter in the offshore zone. This type of variation is expected on 
an eroding profile. However, the mean of the medians in any zone was 
never less than the initial mean median, indicating that the finer frac- 
tions were eroded from the profile surface. 
4. Breaker Characteristics. 
A plot of breaker type and position superimposed on a plot of contour 
movement along range 5 is shown in Figure 22. During the first 30 hours 
the wave broke by plunging and moved seaward as the seaward edge of the 
inshore ‘zone moved seaward. Between 30 and 80 hours the breaker position 
varied across the inshore zone and the breaker type varied between plung- 
ing and spilling. At 60 hours the wave broke twice. From 85 hours until 
the end of the experiment the wave broke twice, generally by spilling and 
occasionally by plunging near the seaward edge of the inshore zone (eleva- 
tion -0.8 foot) and breaking by plunging near the seaward edge of the 
inner inshore region (elevation -0.4 to -0.5 foot). The position of the 
secondary breaker varied across the tank between stations 0 and 8. 
At 56 hours the breaker height (at station 12.5) was 0.47 foot (14.3 
centimeters) along range 1, 0.60 foot along range 5, and 0.52 foot (15.8 
centimeters) along range 9. At 77 hours the breaker height was 0.46 foot 
(14.0 centimeters) at station 5.5 along range 1, 0.54 foot (16.5 centi- 
meters) at station 12.5 along range 5, and 0.45 foot (13.7 centimeters) 
at station 13.0 along range 9. 
5. Wave-Generated Currents. 
The procedures for collecting current data are described in Volume I. 
a. Surface Currents. During the first 35 hours, a circulation 
pattern developed between the breaker zone and the shoreline (Fig. 23), 
apparently as the result of the longshore current which developed at the 
base of the foreshore. The current flowed from landwardmost point of 
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