188 Long Waves in Canals and Standing Waves in Closed Basins 



(with the nodal line at the opening) had a period of 45-5-57-5 min; there is 

 also a transverse oscillation with a period of 21-9-24-5 min. The computed 

 periods were 453 and 23-6 min; the scale model gave 470 and 23-6 min. 

 Figure 80 shows the streamlines of the most frequent oscillations, which 

 were also the easiest to reproduce in the model. 



Tomikowa 



oHakodote 



Fig. 80. Oscillations in the Bay of Hakodate. 



These standing waves have also been observed in the bays and channels 

 of the European coasts, and a mere look at the coastal configurations on 

 charts will suffice to locate the points where they can be expected. Thus, 

 Westphal (1899, p. 53) has been able to find in the tide-gauge registrations 

 seiches-like variations of the ocean surface for a number of German coast 

 localities and Paulsen (1906, p. 13) has done the same for Danish localities 

 around the Baltic and Belts. 



Numerous seiches have been observed in the Mediterranean. Platania 

 (1904-7), Oddone (1908) and Forel (1895, p. 229) have given a compila- 

 tion for a number of localities on the Italian shore. At the west coast of Sicily, 

 from Trapani to Sciacca, there is a phenomenon, referred to as the "Marub- 

 bio", which has the character of seiches with large oscillations of the sea 

 level. Airy identified seiches in the harbour of Malta, which he assumed to 

 be standing waves on the coastal shoal extending towards Sicily and in the 

 Tunisian straits. Kruemmel made the remark that they might be the oscilla- 

 tions of the harbour of La Valetta, with an average period of oscillation 

 of 23-4 min; the dimensions of the bay agree very well with the observed 

 period. 



Seiches-like oscillations exist in the bays and channels of the Adriatic. 

 Stahlberger (1874) has been the first to give a paper on the sea-level registra- 

 tions in the Gulf of Fiume; later on, Mazelle (1907) has tried to derive 

 quantitatively from these registrations the oscillations between the islands 

 and in the numerous bays, which are accompanied by strong currents (called 

 stigazzi). An extensive paper by Sterneck (1914) on the seiches in the 

 Adriatic is available. He has found, from the dimensions of the bays and 



