442 



Tides in the Mediterranean and Adjacent Seas 



external ocean tides on the Gulf tides is greatest. It is remarkable that the 

 range of the spring tides along all the coasts is rather uniform between 1 m 

 (3 ft) and Hm (5 ft). The Magdalen Islands have 0-9 m (3 ft) which in- 

 dicates a decrease towards the centre of the amphidromy. 



In the Strait of Belle Isle there is a transition of the establishment from 

 about 10 h at the Gulf opening to about 7 h in front of the opening into the 

 open ocean, whereas the range decreases slightly. 



200 



160 



120 



80 



E 40 



<u* 



CP 



I 40 

 80 

 120 

 160 



Belle-Isle Str 



Sections of Belle Isle wove- 



Fig. 189. Tides of the Gulf of St. Lawrence co-oscillating with the tides of Cabot Strait 



and the Strait of Belle Isle. 



The analysis of the Gulf tides given by Springstubbe shows that they are 

 almost pure co-oscillating tides. Figure 189 shows the distribution of the 

 ranges of these tidal components along the main axis when co-oscillating 

 at the Cabot Strait and at the Strait of Belle Isle. The nearly complete dis- 

 appearance of the latter component, which formerly was only assumed or 

 even used in the explanation of the amphidromy, is thus proved clearly. 

 The superposition of these two parts of the co-oscillating tides will give an 

 amphidromy rotating to the left and not one rotating to the right, as the 

 observations show. Springstubbe proves mathematically that the latter is an 

 effect solely due to the deflecting force of the rotation of the earth on the 

 tides co-oscillating through the Cabot Strait. The observations on tidal 

 currents agree well with the theoretically computed ones; especially the tidal 

 currents in the Strait of Belle Isle are fully explained. 



For the Gulf of St. Lawrence there are very few harmonic constants 

 available. The few data of Table 67 show that the ratio for the character 

 of the tides is 0-44 near St. Paul in the Cabot Strait and steadily decreases 

 going towards the centre of the Gulf; Quebec has a genuine semi-diurnal type. 



In accordance with the period of the free oscillation of the basin (Cabot 

 Strait — north coast) of approximately 7 h and the small amplitudes of the 



