BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [30] 



is a heavy sash- weight (A, Fig. 6) such as is used for windows by builders. 

 The size to be used will depend upon the depth of water in which work 

 is to be done, but a 10-pound weight is sufficient for ordinary purposes. 

 It will be found convenient to roll the weight up in a stri^) of old can- 

 vas, and have it sewed securely, leaving some of the canvas in front 

 and behind the two ends of the weight. This can then be sewed se- 

 curely to the line with stout twine and will not require to be taken oft'. 

 The author has found that in depths not exceeding 20 fathoms it was 

 sufficient to attach the weight to the short line fixed to the dredge, just 

 behind the point where the short line is attached to the long dredge 

 line. For greater depths of water it should be placed further in ad- 

 vance, and in deep-sea dredging at a considerable distance, owing to 

 the great length of the line used. For the latter work a weight of 50 

 to 100 pounds is sometimes needed. 



ON THE USE OF A DREDGE IN A ROW BOAT. 



Unless the dredge is very light and the water shallow, it is better to 

 have two hands to pull the boat. The boat should be stout and steady,, 



Fig. 6.— Metiiod of using the dredge. 



sufficiently large to hold its own well in the water and sufficiently 

 heavy to avoid being anchored by the dredge when it touches the bot- 

 tom. For most i)urposes one of those heavy boats used on sailing ves- 

 sels, known as a ship's dingey, is perhaiDS the most suitable. The 

 ordinary small light row boat, used for pleasure, is ill-suited for dredg- 

 ing purposes. There should be at the back end of the boat a suffi- 

 ciently solid seat for the dredger to brace his feet against while standing 

 up in charge of the dredge rope. It is advisable also to have room 

 enough between the stroke oar and the dredger to set a tub for the 

 purpose of holding the dredgings. It will also be found more convenient 

 for each man, if two are employed, to pull a single oar rather than two. 

 On getting to the dredging grounds, the dredger, after making sure 

 that his line is clear, free from knots and twists, and securely fastened 

 to the dredge, that the net in the dredge is not turned inside out, but 



