Tides in the Mediterranean and Adjacent Seas 



407 



the Black Sea, both the accurate dynamical solution and the one found by 

 Sterneck differ very little from the solution according to the equilibrium 

 theory, where the Coriolis force is neglected, so that the deviations therefrom 

 should be considered as small corrections. Sterneck's solution, however, 

 shows in certain parts greater deviations than Grace's solution. Anyway, 

 the good agreement with the observations is to be attributed exclusively to 

 the circumstance that the equilibrium theory is by far preponderant. In so 

 far the "exact" computations of Sterneck are useless. This is also shown 

 clearly by the compilation given by Grace in Table 53. The differences between 



Table 53. Comparison between observed and computed 

 values of the tides of the Black Sea 



the results from the simple equilibrium theory and the observations (after 

 Sterneck) are smaller than those between the former and the values computed 

 by Sterneck. In this case the rotation of the earth need not be considered. 

 The tides of the Black Sea, owing to its great depth, are nothing else than the 

 forced oscillations of these water-masses by the tidal forces. 



10. The Tides of the Red Sea 



The shape of the Red Sea makes it especially fit for a test of the dynamical 

 theories of the tides. It is, namely, a simple longstretched basin with steep 

 walls in the direction S. 30° E., which communicates at its southern end 

 through the narrow strait of Bab el Mandeb (smallest cross-section somewhat 

 north of the Island Perim is only 1 7 km 2 ) with the Gulf of Aden and the 

 Indian Ocean. It ends in the north into two narrow canals, namely, the Gulf 

 of Suez and the Gulf of Agaba. The Gulf of Suez is shallow and interspersed 

 with small isles and cliffs (mean depth 118 ft, 36 m), whereas the Gulf of 

 Agaba is deep (average depth 2132 ft, 650 m). Correspondingly, the natural 

 period of the former is 6-7 h, that of the latter 0-9 h. For this reason alone 

 there must be marked differences between the tides in these northern ex- 

 tensions of the Red Sea among themselves and those in the main basin. 



Harris (1904, Part IV, A, p. 649 and Part IV, B, p. 363) was the first to 



