24 THREE CRUISES OF THE ^ BLAKE.” 
had undergone but slight modifications. It consists of a rec- 
tangular frame with flattened sides, to which a bag of net- 
ting is attached, this again being protected by, a canvas bag. 
Fig. 21. — Müller's Dredge. (Thomson. ) 
The dredging-rope is attached 
to one of the wire arms fas- 
tened to the short side of the 
dredge-frame ; the other arm 
is made fast to the first by pont ls 
a stout marline, so that in case 
the dredge fouls, the marline will give way, trip 
the dredge, and not part the rope, which would 
involve the loss of the dredge. The dredges 
used in deep water are generally much larger and 
heavier than those used from small sail-boats. «piis Dredge. 
To prevent the crushing of delicate specimens 
by the dragging of the bag over rough bottoms, a frame-work 
(Fig. 22) has been added to the ordinary dredge; this is cov- 
ered with heavy canvas (Fig. 23), во that the bag with its con- 
tents is relieved of the wear and tear which comes of dragging 
it over the bottom ; the most delicate specimens are thus secured 
uninjured. 
