HOW THE SEA-DEPTHS ARE EXPLORED. 



259 



Fig. 1. 



" Still the thing is possible, and it must be done again and again, 

 as the years pass on, by naturalists of all nations working with im- 

 proved machinery and with ever-increased knowledge. For the bed of 

 the deep sea, the 140,000,000 

 square miles which we have 

 now added to the legitimate 

 field of natural - history re- 

 search, is not a barren waste. 

 It is inhabited by a fauna more 

 rich and varied on account of 

 the enormous extent of the 

 area, and with organisms in 

 many cases apparently even 

 more elaborately ana! delicate- 

 ly formed, and more exquisite- 

 ly beautiful in their soft shades 

 of coloring and in the rain- 

 bow-tints of their wonderful 

 phosphorescence, than the 

 fauna of the well-known belt 

 of shallow watei*, teeming 

 with innumerable invertebrate 

 forms, which fringes the land. 

 And the forms of these hith- 

 erto unknown living beings, 

 and their mode of life and their 

 relations to other organisms, 

 whether living or extinct, and 

 the phenomena and laws of 

 their geographical distribu- 

 tion, must be worked out." 



There are two principal 

 operations in exploring the 

 bottom of the ocean : first, 

 sounding to ascertain depth ; 

 and, second, dredging to bring 

 up materials. Although much 

 ingenuity has been expended 

 in devices to bring up samples 

 of the sea-bottom by the sound- 

 ing-apparatus, yet dredging 



Brooke's Deep-Sea Sottnding-Appabattts. 



contrivances are now mainly relied upon for that purpose. To deter- 

 mine the depth with a sounding-line, it is customary to graduate it by 

 attaching slips of different-colored cloths or leather which mark it off 

 into sections, and give the means of determining the distance to which 



