MUSEUM OF COMPARATIVE ZOOLOGY. 7 
I need not speak to you of the successful working of Captain Sigsbee’s 
water-cup, far superior in efficiency and accuracy to any cup thus far 
employed by the deep-sea explorations preceding us. His modification 
of Thomson's wire sounding-machine, which has now been in use for four 
seasons, has continued to work as successfully as formerly. Though an 
old story to you, to those who are not familiar with the practical work- 
ing of deep-sea soundings as formerly carried on, a few figures enabling 
them to compare the old with the new methods may be interesting. In 
the “Challenger” the deep-sea soundings were made with a rope of eight 
tenths of an inch in circumference, nearly as large as the steel wire rope 
which we used in dredging, and having a breaking weight of 1,200 
pounds, The time occupied in lowering the sounding-machine and its 
weights, often more than 300 pounds, was three to four times as great 
as in.our case. We employed a steel wire (No. 20, American gauge), with 
breaking weight of 240 pounds, only weighted for the deepest soundings 
with a 50-pound shot. The time required to reel in with Captain Sigs- 
bee’s wire machine was always below one minute per 100 fathoms, 
sometimes not more than 20 seconds, while the time required to striko 
bottom averaged from 35 to 45 seconds per 100 fathoms in the deepest 
soundings up to 2,000 fathoms. The steel wire rope, of which I sug- 
zested the use in our dredgings, has worked admirably. In fact, I do 
not see how. with a vessel of the size of the ** Blake " (of only 350 tons), 
we could have found room for the hemp rope necessary for our work. The 
wire rope we used was of galvanized steel with a hemp core; it measured 
one and one eighth inches in circumference, weighing one pound to the 
fathom, with a breaking strain of over 8,600 pounds, as tested by the 
Roebling & Sons’ Company, the manufacturers. We took with us only 
two coils, each of 3,000 fathoms. One coil was on deck, wound to an iron 
reel and frame provided with a friction break for lowering the dredge or 
trawl, the whole space occupied by this length of rope on the reel being 
only five feet long, by four feet wide, and five feet high. In addition to 
the economy. of space thus gained, we were enabled to dispense with 
sending down heavy weights to drag in front of the dredge at a distance 
from the frame, as was invariably done by the **Challenger," the weight 
of the steel rope in water rendering this unnecessary. Our greatest gain 
from the use of steel wire rope came from the rapidity with which we 
could lower and hoist the dredge. In fact, this was done as rapidly as 
is customary in lowering or hoisting skips on the slope of a mine, Our 
usual speed in lowering the dredge until it came within a few fath- 
oms of the bottom was between two and a half and three minutes for 
