340 



SCIENCE. 



[N. 8. Vol. XX. No. 506. 



rapidly contracts in breadth. In latitude 

 45°, it is only half as wide as at the 

 equator. The consequence is that the 

 northward-moving- waters are accelerated 

 to twice their previous velocity. 



^1^^ 



The second condition is that in reaching 

 a higher latitude this accelerated current 

 becomes subjected to a powerful eastward 

 thrust from the rotation of the globe. As 

 its distance from the earth's axis dimin- 

 ishes in going north, its retention of the 

 more rapid eastward rotation acquired at 

 the southward must drive this current with 

 great force to the east. The inevitable re- 

 sult must be that the whole body of cold 

 water going north is driven powerfully 

 against the shores of the North American 

 continent in the latitudes of Sitka and Van- 

 couver's Island. This is illustrated in the 

 accompanying diagram. 



Here then we have two problems, both 

 relating to cold currents. The one con- 

 cerns the source of the mighty Pacific coast 

 current, the other relates to the final out- 

 flow of the deep-sea cold stratum. It is 

 obvious that the two problems fit and solve 

 each other. The answer to both becomes 

 plain. The source of the coast current is 

 in the deep-sea stratum. The outflow of the 

 deep current is the great coast-current. 

 Each fits the other. Together they consti- 

 tute one system. 



The deep-sea current driven by the 

 globe's easterly thrust, and encountering 

 the shoaling ocean bottom, is crowded 

 against the coast, forced to the surface, 

 and driven southwards as its only pos- 

 sible outlet. And so emerges to being the 

 great Pacific coast current. 



Such then is the story of the great Cold- 

 current system of the Pacific. And such 

 is the source of the wonderful cold current 

 of our Pacific coast. It is generated by the 

 massive continental glacier which skirts the 

 Antarctic Circle. It slumbers long in the 

 sluggish womb of the dark Pacific depths. 

 It quickens to activity in the narrowing 

 northern ocean. Finally stung to life by 

 the rotary thrust of the globe, it springs to 

 birth as the mighty current sweeping along 

 the western shores of our continent, dispens- 

 ing coolness and moisture to populous 

 states. And finally it bestows coolness and 

 calm and exemption from tempests to the 

 islands, making a genial paradise of the 

 otherwise sultry Hawaii. All those favored 

 shores derive their genial climes from the 

 transmitted coolness of the Antarctic ice. 



I propound this as a most probable 

 theory of a current system hitherto un- 

 divined. It remains to verify it by sys- 

 tematic soundings and determination of 

 limits of the coast-current. 



S. E. Bishop. 



Honolulu, T. H., 

 February, 1904. 



