12 THE SEAS 



dredgings were made in the great abyss, and nets towed 

 in the water layers between the surface and the bottom. 



The information obtained gave work to a large body of 

 specialists and resulted in the famous " Challenger " reports, 

 which may be said to form the solid base upon which the 

 superstructure of the science of oceanography has since 

 been built. 



These results placed the science on a sure footing, and 

 later expeditions went out with a good idea of the conditions 

 to be expected, so that plans could be laid for special 

 problems of interest that had to be tackled. Better 

 instruments were invented and, most important of all, 

 wire came into general use replacing the old bulky ropes, 

 Alexander Agassiz being the first to use it on the voyages 

 of the Blake, from 1877 to 1880. 



Expeditions sailed from many countries, and since the 

 time of the Challenger some of the more important were the 

 Deep Sea expedition of the Germans in the Valdivia, and 

 the voyages of the National and Deutschland from the same 

 country ; the cruises of the Norwegian vessel, the Michael 

 Sars, under Professor Hjort, and Sir John Murray of 

 Challenger fame ; the famous voyages of Captain Scott 

 and of Sir Ernest Shackleton, and many others. 



Among the more recent cruises have been those of the 

 German cruiser Meteor, which was engaged in making a 

 complete survey of the ocean bed of the South Atlantic and 

 of its current system, and of the Danish research vessel 

 Dana, which has circumnavigated the world. Since 1925 

 too, oceanographical history has been made by the almost 

 continuous observations of the Falkland Islands Depen- 

 dencies' Discovery Expedition in Antarctic waters under- 

 taken, first with Captain Scott's old ship Discovery, and 

 later \vith the modem Discovery II and the William Scoresby. 



In the year 1901 was formed what is known as the 



