OUR KNOWLEDGE OF THE DEEP SEA. 



43 



man Brooke, of the United States Navy, who made the first great 

 improvement in deep-sea sounding in 1854 by inventing a machine 

 in which, applying Causanus's idea of disengaging a weight at- 

 tached to the sounding line, the sinker was detached on striking 

 the bottom and left behind when the tube was drawn up. The 

 arrangement of the parts is shown in the 

 accompanying figure. When the tube B 

 strikes the bottom, the lines A A slack and 

 allow the arms C C to be pulled down by the 

 weight D. When these arms have reached 

 the positions indicated by the dotted lines, 

 the slings supporting the weight have 

 slipped off, and the tube can be hauled up, 

 bringing within it a specimen of the bottom. 

 This implement has been improved from 

 time to time by various officers of our own 

 and foreign navies by changing the manner 

 of slinging and detaching the sinker, and by 

 adding valves to the upper and lower ends 

 of the tube to prevent the specimen from 

 being washed out during the rapid ascent 

 which has been rendered possible by the use 

 of wire sounding line and steam hoisting 

 engines ; but in all the essential features it 

 is the same as the most successful modern 

 sounding apparatus. The impulse given to 

 deep-sea sounding by Brooke was seconded by the successful 

 adaptation of pianoforte wire to use as a sounding line, in 1872, 

 by Sir William Thomson ; and within recent years soundings 

 have been taken far and wide in all the seas by national vessels 

 during their cruises, by vessels engaged in laying submarine 

 cables, and by various specially organized expeditions, among 

 which that known as the Challenger Expedition, sent out by the 

 Government of Great Britain during the period from 1873 to 1876, 

 stands pre-eminent. As a result of this work many of the ques- 

 tions which perplexed the naturalists of the middle of the present 

 century have now been cleared away. 



Many of the specimens of the bottom that were brought up in 

 the early days of deep-sea sounding were studied through the 

 microscopes of Ehrenberg, of Berlin, and Bailey, of West Point. 

 Maury, who believed that there are no currents and no life at the 

 bottom of the sea, wrote : " They all tell the same story. They 

 teach us that the quiet of the grave reigns everywhere in the 

 profound depths of the ocean ; that the repose there is beyond 

 the reach of wind ; it is so perfect that none of the powers of 

 earth, save only the earthquake and volcano can disturb it. The 



