58 FOUNDERS OF OCEANOGRAPHY 



Captain Tizard, who was the Navigating Officer on the 

 " Challenger " during the expedition, tells us that the naval 

 officers on board, equally with the scientific men, were all 

 animated with the idea that it was their business to make 

 the expedition a success, and we understand that while each 

 member of the staff had his own work-room, in which he 

 could pursue his own subject uninterruptedly, they all com- 

 pared notes and got suggestions from one another in the 

 smoking circle after dinner ; a function which, we are told, 

 was always well attended, and where the events and work 

 of the day were freely and amicably discussed. 



The chief hydrographic results which have benefited 

 navigation are, according to Tizard (1895) : — 



(1) The proof that the variation of the compass can be 

 determined as accurately in a ship as on shore, if the ship is 

 magnetically suitable. 



(2) The determination for the first time of the depths and 

 main contour lines of the great ocean basins. It was shown 

 that some of the great depths formerly reported had been 

 much exaggerated, and the deepest sounding obtained was 

 4,475 fathoms, in the neighbourhood of the Mariana Islands 

 in the N. Pacific. The investigations of many other expedi- 

 tions (such as the " Tuscarora," the " Gazelle," the " Vettor 

 Pisani," and the " Valdivia ") since the " Challenger " have 

 not altered in any material degree the contour lines of 

 the great oceans drawn by our expedition in 1876, and have 

 not resulted in the discovery of any depth exceeding 

 5,269 fathoms, about six statute miles. The " Challenger " 

 explorations give no support to the fanciful theory of a lost 

 " Atlantis." Microscopic investigations have revealed no 

 traces of mythical continents now beneath the sea. 



(3) The determination of oceanic temperatures and 

 their independence of seasonal variation below the depth of 

 100 fathoms. 



(4) The proof of constant bottom temperatures over large 

 areas in the ocean. Thus, in the N. Atlantic the temperature 



