lO 



A TEXTBOOK OF OCEANOGRAPHY 



hand the Red Sea with 41 and the Mediterranean with 40 per 

 mille, and the Baltic with from i to 15 per mille. 



EXAMPLES OF SEAS, CLASSIFIED ACCORDING 

 TO SALINITY. 



I. 



Salinity Above Normal. 



Red Sea (37-41). 

 Persian Gulf (37-38). 

 Mediterranean (37-39). 



II. 



Normal. 



Caribbean-Mexico (35- 



36). 

 Bass Straits (355). 

 Gulf of California (35- 



35è)- 



III. 



Below Normal. 



(a) Slightly Uiider. 



Arclic " Océan " (20-35). 

 North Australian Sea 



(33-34)- 

 Bering Sea (28-33). 

 Sea of Okhotsk (30-32). 

 Sea of Japan (30-34). 

 China Sea (25-35). 

 Andaman Sea (30-32). 

 North Sea (31-35). 

 EngHsh Channel (Irish 



Section) (32-35). 

 Gulf of St. Lawrence 



(30-32). 



(b) Miich Beloii'. 



Baltic Sea (3-15). 

 Hudson Bay. 



A classification of seas according to températures is also 

 possible. ' • 



5. Classification according to Movements — i.e., Currents. 



The open océan is the région of the origin of tidal move- 

 ments. Tides are met with in enclosed seas only under certain 

 spécial circumstances. Enclosed seas with narrow entrances — 

 e.g., the Mediterranean — are only subject to tidal waves near 

 the entrance. The tidal effect diminishes the further one gets 

 from the entrance. 



Broadly speaking, the océan is the origin of the great 

 independent tidal waves ; the seas, on the other hand, are the 

 régions of the dépendent tides and currents. Currents are 

 dealt with in greater détail below. 



