of waves at Bermuda was about three times that at the surface and 

 at the Cuttyhunk observations the average period of bottom waves 

 was about two times that at the surface. Furthermore, the longer 

 waves of the complex wave motion are influenced by shallow water 

 effects when approaching the location of recordings from the deep 

 open sea. The results obtained by pressure-records are therefore 

 not strictly comparable with observations at the surface of the open 

 sea. The pressure-recordings evaluated by H. R. Seiwell indicated 

 that ocean wave patterns are not complex interference patterns re- 

 sulting from combinations of several (two or more) distinct waves, 

 but frequently consist of a single wave. This fact is perhaps the 

 consequence of filter-effects: the superimposed shorter waves dis- 

 appear, because they are filtered out by damping. 



During his stay at the Woods Hole Oceanographic Institution in 

 the summer of 1951, the author became aware of new unpublished wave 

 recordings made by Seiwell in 1950 at the sea surface. The director 

 of the Woods Hole Oceanographic Institution was kind enough to per- 

 mit the use of these data and to look into the results of mathemati- 

 cal analysis as far as these data were available.* Unfortunately 

 most of the original data and the results of analysis were lent out, 

 but the remaining part of these observations already seems to indicate 

 important differences compared with the former observations and re- 

 sults, which were obtained at small water depths by pressure record- 

 ings. This new material, collected in 1950 in the vicinity of the 

 Bermudas, comprises sea surface measurements taken by photographic 



*rhe author is very much obliged to Admiral E. H. Smith and Dr. 

 C. 0, D'Iselin for permission to make use of these unpublished 

 data of H. R. Seiwell. 



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