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 strike 

 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- 

 gested the use in ovu* 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,G00 pounds, as tested by the 

 Roebling & Sons' Company, the manufacturers. We took with us only 

 two coils, each of 3,000 fixthoms. 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 



