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keep the dredge-hag at its full length, and prevent it
Fig, 10.—Tlie Dredge.
or the tangles from folding over the mouth of the
dredsre. The dredge-hag is 4 ft. 6 in. in length; the
CMAP. l.J TH E EQ U IPM E N T OF TH E SHIP. 51
loAver halt is of twine netting, so close as to retain
everything except the finest mud, Avhicli indeed only
partially Avashes through, and the upper half is of
tAA’ine netting Avith the meshes an inch to the side.
The hag is guarded by three loops of bolt-rope
attached to the frame of tbe dredge, to tbe bottom of
tbe bag, and finally to tlie tangle-bar. Tbe canvas
pads represented in tbe figure on tbe dredge-frame
are only to protect tbe seizings of tbe loops. Tbe
dredge is suspended from an incb-iron chain, wbicb
forms tbe first fcAV fatboms of tbe dredging-line.
Tbe chain is not, boAvever, directly fastened to tbe
ring at tbe end of tbe arms, but is made fast to
one of the end-bars of tbe dredge-frame, and is
stopped to the ring hy a single strand of holt-rope.
If tbe dredge get caugbt on a rock, a rare occurrence
fortunately in deej) Avater, tbe stop carries
aAvay, tbe direction of tbe strain on tbe dredge is
altered, and it probably relicA’es itself and comes up
end upAvards. In deep Avater a 28 lb. deep-sea lead
is^ usually bung from tbe centre of tbe tangle-bar
AA’itli four tangles on each side.
It is altogether a new experiment to dredge and
to take deep-sea observations from so large a ship,
and it seems to present some special difhculties, or
at all events to require great management, Tbe
AA’eigbt of tbe ship is so great that there can be
no ‘ giA’e and take ’ betAveen her and tbe dredge,
such as Ave have in smaller vessels. I f there be any
Avay on, the impulse to tbe dredge is irresistible;
and it seems to tend to jerk it off tbe ground.
Ibe roll ol the ship, her height above tbe Avatc]-,
her want of flexibility of movement compared Avitli
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