Note that the preceding theory concerns a semi -infinite screen, 

 infinitely thin, and perfectly reflecting; on our model the problem 

 studied differed slightly from the theoretical problem bit was 

 nevertheless very nearly the same in the zone where we have made 

 our measurements. 



Notet The curves given in this paper were calculated before the 



appearance of the approximate theory of diffraction developed 

 by Mr. Lacombe in the Hydro graphique Annals*-. This fact 

 explains why we have not shown the corresponding curves of 

 which the interest is obviously apparent. 



# Editors Note: Note sur la diffraction de la houle en incidence 

 normale, Henri Lacombe, Annales Hydrographiques Paper No. 

 1363, 1949. 



Translated by Dr. Martin A. Mason, Beach Erosion Board. 



24 



