EASTERN PACIFIC EXPEDITION 421 



ant and Mr. Westergren as artist. The Isthmus, which 

 had now become familiar ground to Agassiz, had lately 

 fallen into the possession of the United States, which were 

 just beginning to lay out the work on the canal. Pana- 

 ma, however, was still enjoying its pristine filth, so the 

 party was glad to get on board the Albatross. Here 

 Agassiz took up his abode in the new quarters he had 

 built for himself on the spar-deck, in which he took much 

 satisfaction. On heading to the eastward, after reaching 

 the neighborhood of Chatham Island, the Albatross got 

 well into the Humboldt Current. This mighty river, of 

 which little was previously known, sweeps north off the 

 coast of South America, and veers to the westward south 

 of the Galapagos. Its breadth in many places cannot be 

 much less than nine hundred miles : the western limit 

 of its lower course appears to be about 90° W., while 

 the southern limit of its western extension seems to lie 

 between 10° and 15° S. 



When once within the sweep of this great current, on 

 heading in to the eastward after reaching the neighbor- 

 hood of Chatham Island, the collections became extraor- 

 dinarily rich. Agassiz was among the first to call atten- 

 tion to the fact that the great currents of the ocean teem 

 with animal life, swept along by these mighty rivers in 

 their journeys through the open sea. The abundance 

 of life at the bottom, in the path of such currents, he 

 explained by the amount of dead animal matter that fell 

 from the surface to the bottom, and served for food to 

 the animals living there. 



Agassiz in his report of the expedition has described 

 the richness of animal life within the limits of the 

 Humboldt Current. Whenever the ship was in this vast 

 body of water the tow nets were crowded and brought 



