254 DR. HAROLD JEFFREYS ON TIDAL FRICTION IN SHALLOW SEAS. 
to 1^ to 2 knots. Data are very scanty, but the area affected appears to be about 
70,000 sq. km., leading to a dissipation when the currents are strongest of from 
6 x 10 17 to 1'4 x 10 18 ergs per second. If we adopt the mean of these as giving roughly 
the actual dissipation, and apply the factor 4/37r, we find the average dissipation in 
these gulfs to be about 4xl0 17 ergs per second. There is probably no important 
dissipation elsewhere in the Sea of Okhotsk. 
5. The Bering Sea. 
In the extreme north of the Pacific, between Siberia and Alaska, a chain of small 
islands, the Aleutian Islands, extends all the way across. The region north of these 
has the shape of a quadrant and forms the Bering Sea. Between the islands the 
depth is great, and the tide of the Pacific seems to enter almost unhindered. Since 
the depth of more than half of the sea, mostly on the Alaskan side, is less than 
40 fathoms, large currents are produced, especially in the three chief bays—the Gulf 
of Anadir, Norton Sound, and Bristol Bay. The dissipation must therefore be very 
