250 THE DEPTHS OF THE SEA. [CHAP. VI. 
hemp, 24 inches in circumference, with a breaking 
strain of 24 tons. The 1,000 fathoms next the 
dredge were ‘hawser-laid,’ 2 inches in circumference. 
A Russian hemp rope appears to be the most suit- 
able. A manilla rope is considerably stronger for 
a steady pull, but the fibre is more brittle and liable 
to go at a ‘kink.’ I have never seen a wire-rope used, 
but I should think it would be liable to the same 
objection. The ‘ Challenger’ is to be supplied with 
‘ whale-line’ for her great expedition. The frame of 
one of the dredges which we used in the Bay of 
Biscay is represented at Figs. 47 and 48. The length of 
<----§°---> 
Fic 47.—The End of the Dredge-frame. 
the dredge-frame is 4 ft. 6 in., and it is 6 inches wide 
at the throat or narrowest part. The dredge used in 
the deepest haul was somewhat different. About 
half of each arm next the eye to which the rope was 
attached, was of heavy chain. I doubt greatly, how- 
ever, if this is an advantage. The chain drags along 
in front of the dredge, and may possibly obstruct 
the entrance of objects and injure them more than a 
pair of rigid arms would do. On one side the chain 
was attached to the arm of the dredge by a stop of 
five turns of spun-yarn, so that in case of the dredge 
