MIGRATION AND THE FOOD QUEST. 533 



III. — OCEAN CURRENTS AND FOOD SUPPLY.^ 



lu following" this Hue of enormous food supply our voyagers would 

 be materially aided by the ocean currents. The equatorial stream of 

 the Pacific flows westward between the Tropic of Cancer and the 

 Micronesian axchipelagoes. On reaching the South China Sea it is 

 split, a part going southward and westward into the Indian Ocean and 

 a part northward and eastward, like our Gulf Stream, skirting the 

 outer rim of the seas that I have mentioned all the way to the Columbia 

 Eiver. Within these seas counter currents and eddies help to equalize 

 the temperature of the adjacent lands. The effect of this Kuroshiwo, as 

 the ocean current is called, is much greater uj)on the food supply than 

 upon the people. Bringing millions of tons of tropical silt and low sea 

 forms in its stream, this Nile of the Pacific deposited them over the bed 

 of the landlocked areas, acting like a top-dressing upon soil and a feeder 

 of the aquatic food fauna. The lowering of temperature northward 

 naturally would give the migrants an increased advantage in life's strug- 

 gles as the climate became more stimulating, fecundating, and strength- 

 ening. 



IV. — PREVAILING WINDS AND FOOD. 



As for. the prevailing winds, the trades blow westward in the 

 Tropics. On reaching the Pacific shore they would follow some such 

 law as that of the waters, but during the months of May to October 

 the simoom from the Indian Ocean pushes northeastward and drives 

 the trades along Asia northeastward. As we proceed the ocean current 

 is spread out, and the winds blowing from warmer latitudes exert their 

 benign influences on the coast of southeastern Alaska, British Colum- 

 bia, and the State of Washington. The temperature of the whole route 

 is ecpialized.^ 



^ Cf. Die unfrei-vrillige Wandeningen im grossen Ozean. O. Sillig, Petermanu's 

 Mitteil., vol. 36, Nos. 7 aud 8. 



-1. The annual isotherm — 20*^ to — 10<^ C. I shall call the Arctic area. It includes 

 (1) Arctic America, sweeping below the circle at Hudson Bay; (2) Greenland above 

 75'^ north; (3) Arctic Asia, and pushing down to Jakutsk, in Siberia. 



2. The annual isotherm — 10° to 0-> C, including Alaska south of the strait, north- 

 ern Canada, southern Greenland, Lapland, northern Russia, the northern Altaian 

 piedmont, Okhotsk Sea, Kamchatka. It is the interhemispheric ethnic area. 



3. The annual isotherm, 0° to +10° C, including southeast Alaska, British Colum- 

 bia, southern Canada to New York, southern tip of Greenland, middle or blonde 

 Europe, Mongoloid Asia, northern Japan, southern Saghalien, southern Kamchatka. 



4. 10-" to 20° C, United States, temperature rising west to Rockies by long curve 

 and then southward by precipitous curve; Mediterranean or Melanchroic Europe, 

 central Asia, China, aud Japan. 



5. 20° to 30° C, the tropical world, interior basin of the United States, northern 

 Africa, Mesopotamia, Afghanistan, India, Farther India. 



The summer temjierature of the Yukon region is that of Saghalien, Korea, Japan, 

 aud China. 



The isobar of Hongkong passes along Japanese Isles, around the shore of Okhotsk 

 Sea, across Bering Strait, and crosses America just north of Vancouver. 



