DEPTH OF THE OCEAN. 5 



manner which not only establishes the depth, but brings up specimens 

 of the bottom. The sounding-line in this apparatus is attached to a 

 weighty rod of iron, the lower extremity of which contains a hollow 

 cup for the reception of tallow or some other soft substance. This 

 rod 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 



Fig. 1. Brooke's Sounding Apparatus. 



tension on the line ceases, the swivels are reversed, the slings B are 

 thrown out of the hooks, the ball falls to the ground, and the rod, 

 released from its weight, is easily drawn up, bringing with it portions 

 of the bottom attached to the greasy substance in the cup. By 

 means of this apparatus, specimens of the bottom have been brought 

 up from the depth of four miles. 



