48 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. "JO 



For his three most northerly stations between 35° and 38° north 

 latitude it is the variation in the direction of the wind which princi- 

 pally influences the variations of the surface temperature of the sea, 

 sometimes in the same month, but sometimes in the month follow- 

 ing-. He says " the strength of the winds acts for these stations as 

 an intensifying, but not a causal factor. On the other hand, within 

 the trades and especially for stations 4 to 6, between 18° and 31° 

 north latitude, the strength of the wind is the principal cause, since 

 the direction of the trades may be looked upon in general as pretty 

 constant. The effect of varying strength of northeast trade winds 

 shows itself in the following month, or the next but one, while that 

 of the southeast trades is first noted in the following year, in the 

 surface temperatures of the stations mentioned." 



Although Liepe is of the opinion that the winds on the whole pro- 

 duce a fairly quick and local influence which may be different simul- 

 taneously in different parts of the ocean, he seems also to assume 

 that, for example, the depression of the surface temperature, at 

 least in part, is to be ascribed to the transportation of cold water 

 masses from considerable distances over the ocean. He says, for 

 example (1911, p. 480), that "the existence of uncommonly great 

 quantities of drift ice and icebergs in the Labrador Stream in com- 

 bination wMth a northwesterly direction of the wind may have 

 tended to favor the formation of the so strongly marked negative 

 anomaly of temperature which appears in these stations on the 

 French and Spanish coasts." He seems even to believe that an 

 increased melting of ice in the Arctic regions attending a strong 

 increase of warm water from the Gulf may be effective in depress- 

 ing the surface temperature of the stations. We have to assume 

 that he attributes this to the transportation of cold ice water over 

 the Atlantic Ocean with a mixing with the Gulf Stream water, 

 although he does not express himself clearly to this effect. 



It is interesting to note the good agreement between the yearly 

 curves for the surface temperature at Liepe's station No. i and 

 Petersen's station No. i, which have been assembled by Dr. Peter- 

 sen (see his publication 1912, p. 112). The two curves show also an 

 excellent agreement with our February and March-April curve for 

 the eastward 10° longitude fields, and also for the northeasterly 

 fields of the Portugal-Azores region. This indicates that the varia- 

 tions from year to year for the coldest months of the year cor- 

 respond to the variations for the whole years, a point which we shall 

 later treat more extensively. 



