CHAPTER XVIII. 



MULTITUDINOUS LIFE 



" This great and wide sea, wherein are things creeping innumerable, 

 both small and great beasts." — Ps. civ. 25. 



" The dense immensity 

 Of ever-stirring Life, in thy strange forms 

 Of fish and shell and worm and oozy mud."— Kingsley. 



QOME thirty or forty years ago the know- 

 ^ ledge which man had of the ''Great Deep" 

 was practically nil. 



We know a good deal more now, thanks to 

 the famous voyage of the Challenger, and to 

 many other observations, though still the full 

 sum of our information is small compared with 

 the much that we do not know. 



In the year 1872 the good ship Challenger 

 quitted British shores for her long tour of dis- 

 covery. During nearly three years and a half 

 she cruised about the world, dipping her instru- 

 ments into the water at frequent intervals, 

 measuring the depths, studying the tempera- 

 tures, making note of other conditions, and 



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