lo Natural History Bulletin. 



useful instrument in deeper water, where the bottom generally 

 consists of ooze or fine mud." In our work w^e found the 

 bottom down to our deepest dredging, about two hundred and 

 sixty fathoms, almost invariably rock, and the trawl nets were 

 quickly demolished by the severe usage. It is evident that 

 the trawl can safely be omitted from the equipment of a ves- 

 sel, unless really deep dredgings (sa}' five hundred fathoms) 

 are to be made. 



The dredges were of two patterns. The •• naturalist's "' 

 dredge, for use in shallow water with row-boats or small sail- 

 boats, was made in three sizes, with the frames 15 by 6 

 inches, 18 by 8 inches, and 21 by 10 inches. The largest of 

 these sizes is small enough for any sail-boat work, and still 

 larger sizes would be better for any but the smallest boats. 

 The " Blake "^ dredge has the advantage of a frame to pro- 

 tect the dredge net or bag. In both kinds of dredges it is 

 necessary to punch a series of small holes around the lower 

 edge of the frame, by means of which the dredge nets can be 

 seized to the frames. 



Nets for dredges and trawls can be ordered in any dimen- 

 sions or size of mesh, or in an}- quantit}', of the Gloucester 

 Net and Twine Company, of Boston, Massachusetts, whose 

 long experience enables them to understand the requirements 

 better than any other firm in this country, perhaps. ^ 



In order to protect the dredge nets, it is necessary to make 

 a canvas bag for each, using good new canvas. (We used 

 second hand canvas, to our sorrow.) The mouth of the bag 

 should be as large as the outside of the dredge frame, to 

 which it is securely seized with marline. The bag should 

 be bottomless, so that the water can pass freely through the 

 dredge. It is surprising how soon this dredge covering will 

 be worn out and require renewal. 



At the suggestion of Captain Flowers, we also took along a 



1 Agassiz, "Three Cruises of the Blake," page 24, Fig. 22. 



2 So much difficulty was encountered in finding just where the various items of 

 equipment for marine dredging could be bought, that the author has decided to be ex- 

 plicit in such matters for the benefit of others who may desire to secure similar equip- 

 ment. 



