?A 



On such ridioulously inadequate data must we needs base our 

 present views as to the physical and chemical conditions and cir- 

 culation of the bottom waters of the largest of the oceans. 



On the deeps of the central part of the Indian Ocean (an area 

 roughly as large as Australia) less than a dozen complete serial 

 observations have been taken though information is more extenBive 

 around the African, Indo-LIalaysian and Australian margins. Not^^a 

 single deeo record of salinity has been obtained to the south of 

 Australia," and only six of abyssal temperature, though the Southern 

 Indian Ocean further west has been made comparatively well-lcno'-m by 

 the various Antarctic exploring expeditions. 



Thanhs to the "Meteor," we have today a better picture of the 

 physics of the deep waters of the South Atlantic, in its regional 

 and bathAz-metric aspects, than for any of the other ocean basins as 

 a whol3, an interesting illustration of the amount of exploratory 

 worlv that a single well planned and well equipped deep sea expedi- 

 tion can accomplish. 



The fertility of the results that may be expected from equally 

 detailed surveys of the other oceans may be judged from the fact 

 that the meridional salinity profiles of the two sides of the South 

 and Equatorial Atlantic, constructed from the Meteor's data, have 

 necessitated an entire reconsideration of the views previously held 

 as to the circulatory m.ovements of the different strata in the mid- 

 levels of the Atlantic basins as a whole, especially as to the 

 northward extensions of water from the Antarctic, and as to the 

 regions of sinking and up-welling, 



2, dirculation 



It is as essential for the oceanographer to understand 

 the circulatory .;^ovements of the water, if he is to comprehend any 

 of the events that take place in the sea, whether biologic or geo- 

 physical, as it is for the meteorologist to understand the systems 

 of winds on land. 



In practice, the study of ocean currents can never be divorced 

 from that of the more static physical features of the water as repre- 

 sented by salinity and temperature, both because the latter give 

 evidences of the former, and because the circulation is largely 

 responsible for the distribution of temperature and salinity, as 

 actually existing. It is, in fact, chiefly because of the trans- 

 ference toward the poles of great volii;:ieE of water that have been 

 heated near the equator by the sun, because of the return movements 

 toward the tropics of water cooled around the Arctic and Antarctic 

 fronts, and because of the mass sinkings in high la.titudes, that the 

 distribution of ter.perature in the sea does not vary directly v/ith 

 the latitude, but that an as^nrnmstrical distribution is maintained, 

 warmest in the eastern sides of the oceans in the northern hemisphere, 

 in the western sides in the southern, and that the abyssal basins 



1. This is ccntrolled to some extent by difforences in the efficiency 

 of alternate eum;:ier warming and winter cooling, in situ , along the 

 windward and leeward sides of the continents. 



