6 THE BOTTOM OF THE SEA. 



supported a certain distance up the rod, on which i<^ 

 slides freely, by means of the sling dd, the ends of 

 which are looped on to the moveable ears at the top 

 of the rod. To these also the line is attached by 

 which the apparatus is lowered into the ocean. Thi 

 weight of the shot, being sufficient to resist a curreni 

 carries the line down perpendicularly ; and when th« 

 protruding end of the rod strikes the bottom (fig. 3) 

 the line slackens, the moveable ends drop, and th« 

 loops of the sling are disengaged. The shot thei 

 slides down the rod, and the latter, no longer en 

 cumbered with the weight a, can be drawn up wit) 

 ease. It will be seen that a sort of cup is formed a 

 the lower end of the rod, and this is " armed " witi 

 soap or tallow, so that a specimen of the submarin 

 •cioil may adhere to it : or the barrel of a commoi 

 quill is attached to the rod, which is said to answe 

 better. By either contrivance specimens of the sea 

 bottom have been brought up from a depth of nearb 

 four miles. Every time this apparatus is used th( 

 shot and sling are of course lost, the rod alone being 

 recovered when the line is pulled in. 



Attempts to sound the sea before the invention of 

 this method have produced results which are now 

 regarded as being of little or no value. The 

 honour of having made the first attempt belongs 

 to Peter the Great, who constructed an apparatus 



