The Mighty Deep 



Nothing is known of it now by direct per- 

 sonal observation. No living man may penetrate 

 those depths. The only mode in which we can 

 learn what is, what lives, what happens there, is 

 by means of "soundings," by sending down and 

 drawing up specially prepared instruments, the 

 reading of which gives us information about that 

 Under- world. 



Soundings made in earlier times did little 

 more than tell navigators how deep the sea 

 thereabout might be. Such instruments as were 

 then used could neither work beyond a limited 

 depth, nor say their say with accuracy. 



Of late years immense improvements have 

 taken place, both in the make of the machines 

 employed, and in the methods of working them. 

 Past soundings were few and unsystematic ; 

 whereas now they are many and by rule. Ther- 

 mometers have been made which bring up from 

 the bottom of the sea reports of the prevail- 

 ing heat or cold, moving unaffected through 

 warm or cold layers between. Specimens of 

 the materials which lie on the ocean - floor 

 have been brought to light, and analysed. 

 Living creatures in great numbers have been 

 hauled from their own domains, examined and 

 classified. 



38 



