28 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 70 



Petterssoii also tried to show that there are great variations from 

 year to year in the Atlantic current of the Norwegian sea. These 

 he regarded provisionally as non-periodic and also to be at least 

 partially explained by variations in the melting of the ice. We 

 have at several earlier opportunities taken issue with this ice-melt- 

 ing theory, and we will not go into it again at this place. 



In his later works (1912, 1914) Pettersson believes himself to 

 have shown that in the course of long intervals great changes in 

 the climate of the earth take place (similar to those which Hunt- 

 ington maintains) and also in the circulation of the oceans. These 

 changes he regards as in greater part periodic and due to cosmic 

 causes. We should be led too far if we should undertake to examine 

 these studies. 



be cited the condition of the Atlantic Ocean within and north of the Sargasso 

 Sea. He says (1905, p. 27) : "Between 26° and 30° north latitude, the water 

 has an upward tendency, and on the surface the water flows on the one hand 

 toward the equator and on the other toward the North Atlantic. The velocity 

 in the latter direction is the largest, 47 cm. per second, that has been observed 

 in the Atlantic Ocean. According to my view this lively water circulation is 

 to be regarded as due to the influence of the melting of ice near Newfound- 

 land. This important phenomenon for ocean circulation acts periodically with 

 the season of the year. On account of the influence of the seasons upon the 

 melting of the ice and the direction of the wind, the pressure and density 

 distribution in the ocean can have no stationary condition." These conse- 

 quences he bases upon Schott's longitude section through the Atlantic Ocean 

 along the meridian of 30° east, which he has converted into a dynamic section. 

 The steepness of the curves (of isotherms and lines of equal density) in this 

 section north of the zone between 20° and 30° north latitude is obviously in 

 a large part due to the eastward directed motion of the water masses of the 

 Gulf Stream upon the north side of the Sargasso Sea. From this very steep- 

 ness it results that the velocity of the currents is so large. By depressions or 

 elevations of the lighter surface water on the right hand side of the ocean 

 currents in the northern hemisphere (therefore on the inner side of the anti- 

 cyclonic motion as in the Sargasso Sea) there is produced a heaping up, — that 

 is, a depression of curves of the warmer surface water in the middle of this 

 sea which Schott's section very plainly shows. 



The " heaping up " of the ground water at the equator as well as the " cold 

 up-rush " on the northwest coast of Africa and the " cold wall " on the east 

 coast of North America, which according to Pettersson are due to hindrances 

 in the motion of the ground water, are really examples of more or less sta- 

 tionary conditions which are produced because the colder lower layers at the 

 left side of the ocean currents are pushed up in consequence of the operation 

 of the rotation of the earth. The " cold wall " lies on the left side of the Gulf 

 'Stream along the east coast of North America. The " cold up-rush " on the 

 northwest coast of Africa lies on the left hand of the Canary current and the 

 " heaping up " of the ground water on the north side of the equator lies along 

 the left side of the northerly equatorial current. 



