148 SATURDAY LECTURES. 



I have alread}' spoken of the attempts at securing speci- 

 mens of the bottom which accompanied sounding by vari- 

 ous methods. It is evident that the amount of material 

 which can be obtained by even the best modern sounding 

 apparatus is too small to give any adequate idea of plants 

 or animals which might exist on the sea bottom. This fol- 

 lows both because only the smallest animals could find en- 

 trance into the tubes intended to bring up .specimens of 

 bottom, and also because the apparatus is not fitted nor in- 

 tended for the purpose of capturing living animals, and if 

 any existed on the spot struck by the lead the blow would 

 probabl}^ reduce them to fragments. 



Other means are then necessary for this purpose, and 

 since deep-.sea explorations have lately included both dredg- 

 ing and sounding as well as temperature observations and 

 collection of water-samples, I shall proceed to describe the 

 various instruments used for these purposes before consider- 

 ing the work accomplished by them. 



The dredge and trawl are instruments which have been 

 used from time immemorial by fishermen, and which, in a 

 modified form, are employed in the deep sea for the capture 

 of its inhabitants. The naturalist's dredge was designed in 

 nearly its present form by O. F. Mliller, of Denmark, a very 

 distinguished early naturalist, more than a century ago. 

 It has been made more convenient and effective, but the 

 modifications are very slight. The best form seems to be 

 that adopted thirty years ago by Dr. Stimpson, and used by 

 American naturalists ever since. It comprises a frame of 

 heavy iron forming a parallelogram, the two long sides bev- 

 eled outward to act as scrapers ; it is perforated along the 

 hinder edge with a row of small holes, into which a net 

 and two flaps of canvas are laced with copper Avire. The 

 canvas is outside of the net and longer than the latter, and 

 protects it from being cut by sharp stones on the bottom as 

 it drags half full of mud behind the frame. Two movable 

 arms project forward from holes in the short sides of the 

 iron frame, coming together about two feet in front of it, to 

 one of which the dredge-rope is attached ; but the other is 



