the use of the "Significant" height and period is therefore just as 
much in error as the analysis of a pressure record in terms of 
these values. For sea conditions, the results are meaningless. 
"En echelon" waves can also be treated by these considerations. 
Suppose that a given filter from some storm has a narrow ® band 
width and a wide # band width. Then the waves in deep water will 
have relatively long crests. Upon refraction, the long narrow 
spectrum becomes an arc, and evaluation of the finite net would 
then show the "en echelon" effect. The apparent crests would be 
shorter along the crests after refraction than before refraction. 
pomgese nad pho esnanhs 
In this section two very fascinating aerial photographs and 
some enlargements of parts of these photographs will be discussed 
in detail. These photographs were furnished by Mr. Dean F. Bumpus 
of Woods Hole Oceanographic Institution. They are both very clear- 
cut examples of the refraction of a Gaussian short crested sea sur- 
face. They were taken along the coast of North Carolina at Oracoke 
and Swash Inlet by the Coast and Geodetic Survey on January 24, 
1945. Figure 33 is an aerial photograph over Oracoke. Figure 34 
is an aerial photograph over Swash Inlet. Figures 35, 36, and 37 
are enlargements of parts of figures 33 and 34 for easily recog- 
nized areas. 
Both photographs show some very interesting features. In the 
deeper water on the right, the longer crests are at about an angle 
of forty-five degrees to the coast line. The lengths of the apparent 
crests are quite short. Half way between the edge of the photo and 
the coast, the crests are more nearly parallel to the coast and 
69 
