CONCLUSIONS— NORTHERLY CURRENT 



Table XV. Siimynarized relation of phosphate reduction to volume of 

 phytoplankton off Cape Carranza, Antofagasta and San Juan 



189 



The data in this table are computed from the figures set forth in Table XIV. Data collected at Sts. WS 

 652-654 in the region of the warm-water wedge have been omitted. 



CONCLUSIONS ON THE RESULTS OBTAINED 



CURRENT 



The surface circulation on the west coast needs to be examined more fully than has 

 been possible on the present survey before an exhaustive account of the region can be 

 rendered. The water-masses composing the uppermost layers share in the anticyclonic 

 gyratory movement of the eastern South Pacific; but throughout our results run 

 evidences of larger and smaller eddies which give rise to counter-currents of supreme 

 importance to the coastal biology. At the surface this movement has been recorded 

 directly by the set and drift of the ship, and indirectly by other hydrological data. 

 Movement beneath the surface has been inferred by indirect means only. 



NORTHERLY CURRENT 



Surface Current. A study of the ship's drift has been made on pp. 125-133, where 

 it was shown to be northerly at irregular intervals, greater inshore with a mean north- 

 ward velocity of 10-12 miles a day than at a distance of 100-130 miles, where the mean 

 northward velocity was only 3I miles a day. Seldom was there a sudden change from 

 the zone of heavier drift to that of lesser, but the mean values over the whole coast 

 showed a slow diminution with increasing distance from shore. Winds, on the other 

 hand, are stronger offshore than inshore. It follows that the influence of current on the 

 drift of the ship in a direction parallel to the coast is greatest inshore.^ It is reported 

 that steamers take one-tenth longer on a given run going south than going north, and 

 that near Antofagasta fishermen find difficulty in working southwards under sail (Coker, 

 191 8). It is of historical interest, too, that Betagh, when masquerading as a Spaniard in a 

 prize captured off the Peruvian coast, was challenged by an enemy vessel and he used 



1 See footnote on p. 190. 



