April 14, 1905.] 



SCIENCE. 



573 



100 miles, to over 1,100 fathoms within a 

 comparatively short distance from both 

 Sala y Gomez and Easter Island. 



The southern part of our line from 

 Easter Island to the Galapagos shows all 

 the features characteristic of the western 

 part of the line from Callao to Easter 

 Island ; like the latter, as far as the twelfth 

 degree of southern latitude, it proved com- 

 paratively barren, the bottom consisting of 

 manganese nodules to within about 250 

 miles of the Galapagos. The pelagic and 

 intermediate fauna from Easter Island to 

 12° south latitude was very poor, and the 

 serial temperatures show that we were out- 

 side and to the westward of the great Hum- 

 boldt current. But near the twelfth degree 

 of southern latitude a sudden change took 

 place; the pelagic and intermediate fauna 

 became quite abundant again, and soon 

 fully as rich as at any time in the Hum- 

 boldt current. There was also a marked 

 change in the temperature of the water as 

 indicated by the serials, showing that from 

 the twelfth degree of southern latitude to 

 the Galapagos we were cutting across the 

 western part of the Humboldt current. 

 The great changes of temperature which 

 took place in the layers of the . water be- 

 tween 50 and 300 fathoms are most strik- 

 ing, and show what a disturbing element 

 the great mass of cold water flowing north 

 must be in the equatorial regions of the 

 Panamic district to the south and to the 

 north of the Galapagos. South of the 

 Galapagos the western flow of the Hum- 

 boldt current must be nearly 900 miles 

 wide, and of about the same width when 

 running parallel to the South American 

 coast. 



The range of temperatures between 30 

 fathoms and 150 fathoms is at some points 

 as great as 21°. Such extremes can not 

 fail to affect the distribution of the pelagic 

 fauna, and may account for the mass of 

 dead material often collected in the inter- 



mediate tows at depths of less than 300 

 fathoms, when the range becomes as great 

 as 28°. Such a range of temperature is 

 far greater than that of the isocrymic lines 

 which separate coast faunal divisions. The 

 bottom fauna, as we entered the Humboldt 

 current going north, gradually became 

 richer in spite of its being covered with 

 manganese nodules. 



The two lines centering at Easter Island 

 developed the Albatross Plateau indicated 

 on the Challenger bathymetrical charts, on 

 the strength of a few soundings reaching 

 from Callao in a northwesterly direction 

 and of a couple of soundings on the twen- 

 tieth degree of latitude. The Albatross 

 Plateau is marked as a broad ridge sep- 

 arating the Buchan Basin from the deep 

 basin to the westward, of which Grey Deep 

 and Moser Basin are the most noted areas. 



Our line from Easter Island to the Gala- 

 pagos showed a wonderfully level ridge, 

 varying in depth only from 2,020 to 2,265 

 fathoms in a distance of nearly 2,000 miles. 

 The soundings we made to the eastward 

 from the Galapagos to the South American 

 coast, and to the westward of Callao, as 

 well as on the line from Callao to Easter 

 Island, all indicate a gradual deepening to 

 the eastward to form what the Challenger 

 has called the Buchan Basin, with greatest 

 depths of 2,400 to over 2,700 fathoms, 

 and passing at several points near the coast 

 to Milne-Edwards Deep, Haeckel Deep, 

 Kriimmel Deep and Richards Deep, some 

 of them with a depth of over 4,000 fathoms. 

 According to the Challenger soundings the 

 Juan Fernandez Plateau connects with the 

 Albatross Plateau and forms the southern 

 limit separating Buchan Basin from the 

 Barker Basin to the south of the Juan 

 Fernandez Plateau. 



At Easter Island Ave found our collier 

 awaiting our arrival. We moved from 

 Cook Bay to La Perouse Bay to coal, as 

 there was less swell there than in Cook Bay, 



