METHODS OF RESEARCH 9 



was added to the charts of the known world 

 almost at a single bound. 



It is interesting to note that Magellan, when 

 crossing the Pacific in 1521, attempted to 

 sound the open ocean ; his short line failed 

 to reach the bottom, and he naively concluded 

 that he had discovered the deepest part of 

 the ocean. 



The early voyages in the sixteenth and 

 seventeenth centuries led to a vast increase 

 of knowledge of the superficial extent of the 

 various oceans, their currents, tides, winds, 

 temperature, and salinity. True deep-sea 

 soundings were taken by Captain Cook during 

 the second half of the eighteenth century, 

 by Captain Phipps in the Arctic in 1773, 

 by Sir John Ross in the Arctic in 1818, and 

 by Sir James Clark Ross in the Antarctic 

 in 1840, all these, except when in very deep 

 water, being fairly accurate. 



The proposal to lay an electric cable 

 between Europe and America gave a great 

 impetus to oceanographical investigations, and 

 led to great improvements in the apparatus 

 for taking deep-sea soundings. About 1850 

 Brooke introduced a method of detaching the 

 heavy weight used to carry down the line 

 and tube ; on striking the bottom the weight 

 was left there, and the tube with its sample 

 of bottom-deposit was hauled up to the 



