Nakkatu'I': ok Bahama Expedition. ii 



small oyster dredge, such as is used in the Chesapeake. This 

 we found of excellent service on shallow, sandy bottom, such 

 as the Bahama Banks, but it will not do to use it on rock\- 

 bottom, as the teeth get such a tirm grip on the rocks that 

 there is danger of disastrous breakage of some part of the 

 dredging equipment. Such a dredge with the teeth broken out 

 would probably do good service if lined with netting, to pre\'ent 

 the loss of the smaller and more delicate objects. No matter 

 what kind of dredge is used, it should be stronglv built, and 

 hung so that it will '• trip " before breaking the dredge rope. 

 This is effected bv fastening only one of the iron arms of the 

 dredge frame directly to the dredge rope, the other arm being- 

 lashed to the hrst by marline, which, when the dredge fouls 

 on the bottom, will usually break, allowing the dredge to be 

 extricated without breaking the dredge rope, involving a loss 

 both of dredge and rope. We found in practice that the 

 tendenc\' is to underestimate the strength of the marline, 

 making the lashing so strong that the dredge frame itself 

 bends in order to slip by the obstruction, instead of the tension 

 being relieved bv the breaking of the marline. 



The necessity of heavily weighting the trawls and dredges 

 is obviated by use of the iron rope, which tends by its own 

 weight to take the dredge to the bottom. We found, how- 

 ever, that a forty or fifty pound weight attached a short 

 distance in front of the dredge facilitated matters consider- 

 ably, and usually insured successful hauls at the depth at 

 which we worked. When the •• Blake " dredge is used, a 

 couple of twenty pound weights attached to the lower end of 

 the frame will tend to keep the front edge from digging into 

 the bottom. Lead weights at eight cents per pound are 

 rather expensive material for sinking dredges or tangles. If 

 any considerable amount of work is to be undertaken.it would 

 be cheaper in the end to have a number of castings made in 

 the shape of iron balls, with rings for lashings. These 

 could be provided in various sizes, and thus save considerable 

 expense. In spite of every precaution, a number of weights 

 will be lost. In using lead sinkers we were surprised to see 



