CONCLUSIONS— COUNTER-CURRENTS 191 



sideration of the fact that the surface water moves away from the coast towards the 

 west, suggests that layers below move toward the east to compensate for the water 

 which is welling up (Schott, 1891, p. 215): this is suggested too by isohalines in Figs. 

 47, 49 and 50. If this is the case, the northerly extension of sub-Antarctic water beneath 

 subtropical water may be regarded as a mid-water current of compensation associated 

 with the coast. 



SOUTHERLY CURRENT 



Surface Current. Southerly current close against the coast, to which references 

 are very frequent in the literature, was met off Capo Blanco, Antofagasta and Caldera 

 (Figs. 14 and 15, and Table I). Inshore of the Lobos Islands, the distribution of surface 

 salinity suggests that a similar coastal counter-current may have been present. These 

 counter-currents were of small dimensions and were seldom more than 2-3 miles in 

 width ; we have in consequence few data relating to them. They occurred in regions 

 where water movement, and especially movement towards the north and west, was con- 

 spicuous and where, therefore, upwelling on a corresponding scale might be expected. 

 In the neighbourhood of the counter-currents, however, upwelling was locally allayed 

 and the counter-currents seem to have been in part currents of compensation. They are 

 thus seen to constitute a series of eddies and are probably such as may be found on any 

 coast. These eddies are cyclonic and the convergence of the counter-currents with the 

 coast is presumably an expression of the tendency to deflect cum sole. At Caldera the 

 surface drift is illustrated diagrammatically in Fig. 8, while the depth reached by an 

 eddy-like mass of sinking water is illustrated by the section in Fig. 23. 



Records of southerly drift at some distance from the coast do exist but are 

 fewer (Frezier, 1716; Juan and Ulloa, 1748; Belcher, 1843; and Stiglich, 1925): 

 according to Romme (1806): 



Pres de cette cote, les eaux se dirigent au N, tandis qu'au large elles s'avancent vers le sud. 

 A Arica suivent Frezier, les courans, en ete, portent au N et au NO; mais en hiver, au sud. Devani 

 Callao et dans les parages voisins, on a observe, au large, un courant dirige au sud, tandis que le long 

 de la cote, les eaux s'avan9aient dans le nord. — A 80 lieues en mer, entre les paraileles de 15° S et la 

 ligne, et meme jusqu'a 15° N, les courans portent generalement a ouest, et ils s'avancent dans le sud, 

 sous des latitudes plus grandes que 5° sud. 



A highly saline warm-water wedge which during the present survey lay in the open 

 ocean was well away from the coast, had a breadth of some 50 miles and seemed to extend 

 along the greater part of the Peruvian coast ; it was thus of considerable dimensions 

 (Fig. 16). High salinity and temperature and a breadth which varied little were the 

 distinguishing characteristics of this wedge, but southerly flow was recorded off San 

 Juan and off northern Peru. Upon these facts, the conception of a counter-current 

 based, though its acceptance as a continuous counter-current leaves much to be 

 explained. Moreover, the observations in the wedge off Callao and San Juan, are 

 separated by about 270 miles, and in this distance no data are available except close 

 to the coast. 



