SUBMARINE BELLS CURRENTS. 51 



Submarine bells. — These may be placed in the following posi- 

 tions: (1) Light- vessels, (2) buoys, where they are worked by the 

 motion of the sea, and (3) on the sea bottom, where they are con- 

 trolled electrically from shore stations. Their effective range far ex- 

 ceeds that of aerial sound signals, having been known to exceed 15 

 miles; and their bearing can be determined with sufficient accuracy 

 for safe navigation in a fog, if a vessel is equipped with telephonic 

 receivers. Even should a vessel not be so equipped, the submarine bell 

 can be heard from below the water line for distances that are well out- 

 side the range of aerial fog signals, though its bearing can not then be 

 so Avell determined. 



Currents — Gulf stream. — The Gulf stream, after running north- 

 ward and northeastward oft' the coast of the United States, turns 

 more decidedly to the eastward between the parallels of 35° and 40° 

 N. latitude, and passes southward of the Great bank of Newfound- 

 land during winter, but extends over the southern end of that bank 

 during summer. It thus has an oscillatory motion, and it spreads out 

 into streaks, which sway about in their course and are of warm and 

 colder water, so that it is impossible to assign any definite limits to 

 its margins. 



The rate of the Gulf stream southward of the Great Bank of New- 

 foundland is very variable, but it generally is from 10 to 35 miles 

 a day. 



Arctic current. — The cold Arctic or Labrador current sets south- 

 ward from the Arctic ocean and Baffin bay and passes through Davis 

 strait and along the coast of Labrador and the east coast of New- 

 foundland. It is very much influenced near the land by the winds and 

 reaches its greatest rate after those from the northward. 



A cold current also sets southwestward along the east coast of 

 Greenland, and abreast Labrador these currents appear to extend east- 

 ward to longitude 40° W. The line of meeting of the southgoing 

 currents with the northern edge of the Gulf stream is nearly always 

 marked by rips. 



Northward of 50° N. latitude detailed information on currents is 

 very scanty. The movement of the water appears to be principally 

 due to wind and to be very slight, except the currents along the east 

 coasts of Greenland and Labrador, which are known to be practically 

 permanent and of considerable strength. 



In the offing of the coast of Labrador the average rate of the cur- 

 rent is said to be about 6 miles a day, but off some of the headlands 

 its rate reaches 2 miles an hour and possibly more. The Arctic cur- 

 rent does not attain any great rate within some 25 miles from the 

 coast between cape Bonavista and Cape Spear ; it appears to skirt the 

 northern side of Fogo islands and extends out to Funk island, thence 

 turning southward ; it often binds the field ice into Notre Dame and 

 Bonavista bays and the mouth of Trinity bay. 



