CHAP. VI. ] DEEP-SEA DREDGING. yl 
cates roughly whether the dredge is going down 
properly. When it reaches the ground and begins 
to scrape, an experienced hand upon the rope can 
usually at once detect a tremor given to the dredge 
by the scraper passing over the irregularities of the 
bottom. The due amount of rope is then paid out, 
and the rope hitched to a bench or rollock-pin. 
When there is anything of a current, from what- 
ever cause, it is usually convenient to attach a weight 
varying from fourteen pounds to half a hundred- 
weight, to the rope three or four fathoms in front of 
the dredge. This prevents in some degree the 
lifting of the mouth of the dredge. If the weight 
be attached nearer the dredge, it is apt to injure 
delicate objects passing in. 
The boat should move very slowly, probably not 
faster than a mile an hour. In still water, or with 
a very slight current, the dredge of course anchors 
the boat, and oars or sails are necessary; but if 
the boat be moving at all it is all that is required. 
I like best to dredge with a close-reefed sail before a 
light wind, with weights, against a very slight tide 
or current; but these are conditions which cannot 
always be commanded. ‘The dredge may remain 
down from a quarter of an hour to twenty minutes, 
by which time, if things go well, it ought to be 
fairly filled. 
In dredging from a small boat the simplest plan is 
for two or three men to haul in hand over hand and 
coil in the bottom of the boat. For a large yawl 
or yacht, and for depths beyond fifty fathoms, a 
winch is a great assistance. The rope takes a couple 
of turns round the winch, which is worked by two 
