20 



THE POPULAR SCIENCE MONTHLY. 



first failure. These soundings and grapplings bi'ought from the sea- 

 depths unmistakable proof that life in many varied and exquisite 

 forms existed there, far away from light and vegetation, under an 

 enormous pressure of superincumbent waters ; and logic retired dis- 

 comfited. 



The fact that the JEgean Sea is empty of life in its greatest depths 

 is due to local causes. The humblest life, in the farthest recesses of 

 the ocean's bed, is, in some of its essential features, but a sluggish 

 copy of the higher types on land. Food and air are alike necessaiy 



Fig. 4. Genebativb Bcds of Tubularia indivisa. (From Female Colony.) 



to both. The circulation of currents throughout the open seas bears 

 nutriment and oxygen to the lowly forms of animal life which lie far 

 below the level penetrated by light, or capable of supporting vegeta- 

 tion. In the Mediterranean such currents are obstructed by the high 

 rocky wall which runs under the straits of Gibraltar, from Spain to 

 Africa. The lowest point in this wall is 10,000 feet above some por- 

 tions of the bed of the Mediterranean. The currents in this sea are 

 therefore superficial, as well as the life sustained by them. 



Chemical analysis proves that the water of the open seas contains 



