DEPTH OF THE OCEAN. 
which not only establishes the depth, but brings up specimens of 
the bottom. The sounding-line in this apparatus is attached to a 
"’eighty rod of iron, the lower extremity of which contains a hollow 
cup for the reception of tallow or some other soft substance. This 
r °d is passed through a hole in a thirty-two pound spherical shot, being 
supported in its position by slings a, which are hooked on to the line 
by the swivels a. When the rod strikes the bottom, the tension on 
l*'ig. !. Brooke’s Sounding Apparatus 
the line ceases, the swivels are reversed, the slings n are thrown out 
°t the hooks, the ball falls to the ground, and the rod, released from 
its weight, is easily drawn up, bringing with it portions ot the bottom 
attached to the greasy substance in the cup. By means of this ap- 
paratus, specimens of the bottom have been brought up from the 
depth of four miles. 
