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Verrill and Messrs. Goode and Bean of the AYashinixton 

 Musenm spent part of Jnly and August at Salem. One 

 of the old stores on Derby wharf was used for the shore 

 work, and a steamer was sent by the Navy department to 

 carry on the dredging. The time was too short to spend 

 much of it on the shallow water animals, and every day, 

 when the weather allowed, the steamer was used for 

 dredging in the deeper water ten to twenty miles from 

 shore in depths of forty to one hundred fathoms. The 

 instrument usually employed is a dredge consisting of an 

 oblong frame of iron about two feet wide, behind which 

 drags a net protected by canvas. After ascertaining the 

 depth and temperature of the water and character of the 

 bottom by sounding, the dredge is lowered and the vessel 

 allowed to drift with the current, drawing the dredge 

 slowly over the bottom and scraping up whatever it 

 meets. After sufficient time, the dredge is hauled in by 

 the help of a steam windlass, and the contents tipped into 

 a sieve hung over the ship's side ; the larger animals are 

 picked out and the dirt is washed by a stream of water 

 until the finest part passes through the sieve and leaves 

 the shells and larger objects in sight. The contents of 

 the sieve are then carefully picked over and the animals 

 either put into vessels of clear water, to be carried ashore 

 living, or into alcohol. On smooth bottoms a larger kind 

 of dredge, called a trawl, is used. This consists of a 

 net fifteen or twenty feet wide at the mouth, the upper 

 half of which is attached to a beam supported at the ends 

 by runners, while the lower half is weighed down so as 

 to drag on the bottom. The net has, along the sides, 

 pockets in which fishes trying to escape find themselves 

 entangled. In the trawl not only the bottom fishes, but 

 all the animals that are not buried in the mud, are brought 

 up. Sometimes a stone weighing several hundred pounds 



ESSEX INST. BULLETIN. IX 10 



