808 EIGHTH PACIFIC SCIENCE CONGRESS 



April 1941 (Fig. 9) shows for example that the isotherms for 26°, 

 25° and 24° at the peak of the invasion of the warm waters must have 

 had a direction from approximately WSW-ENE. It seems improbable 

 that they turn further offshore to the direction jSTW'-ES in ordei- to 

 show up again off Ilo and Arica. Should we believe that the high 

 temperatures reach this region as consequence of the invasion of warm 

 waters from the NW and are curtailed when the invasion reaches the 

 culminating point (isotherms stressed out WSW-ENE), or is there a 

 steady flux of new warm water from another source? We must also take 

 in account that the elevation of temperature off Mollendo-Arica is 

 practically a constant phenomenon, although the amplitude of the varia- 

 tion of temperature is less in winter time. 



On the other hand, according to the map published by Schott and 

 Sthu, (quoted from Gunther, 1936), surface temperatures of 22°-20° 

 are traced as belonging to the latitudes 17°-20°S in the open ocean 

 far away from the Continental Coast, deflected, however, some 1200 

 miles offshore in the NE direction, by the northerly movement of the 

 waters along the coast of South America. Their position during March 

 1891 and 1925, makes us look with awe at the overwhelming forces of 

 the Equatorial Countercurrent, which stemmed back these isotherms to 

 their position in the outer ocean over an area of nearly 1200 miles wide 

 in those latitudes. We see now that none of the perturbances of 1939, 

 1941 and 1953 can be compared with the catastrophes of 1891 and 1925, 

 which for their part restituted for a short time the hydrographical and 

 meteorological situation corresponding to the geographical latitudes of 

 the coast involved, where the cool water of the Peruvian Current has 

 created a thermic anomaly of such a magnitude. 



None of our maps entitles us to draw the isotherms in the zone off 

 Ilo-Arica-Iquique in the same manner as for 1891 and 1925. The iso- 

 therm for 25° situated there has therefore been left open without sug- 

 gesting any solution of our problem. 



Nevertheless, it might be possible to look for an explanation of 

 this phenomenon off Ilo and Arica, and the other one, created by the 

 warm water off Chimbote, in the hypothesis of Gunther (1936). He 

 supposes the existence of two different countercurrents, "warm wedges", 

 off the Peruvian Coast which flow in a southeasterly direction, one start- 

 ing more or less off Aguja Point and reaching as far as the latitude of 

 Callao and the other one coming out of a region WSW of Pisco and 

 entering near the coast just off the bay of Arica. Both these counter- 

 currents transport, according to the vieAv of Gunther, warm water from 

 the NW to the SE. The author of this paper has objected (1943) 

 against the existence of these two "warm wedges", because Gunther cor- 



