48 FOUNDERS OF OCEANOGRAPHY 



of 4,500 fathoms the sounding weight took an hour and a 

 quarter to reach the bottom, and a much longer time to wind 

 in again. It used to take all day to dredge and trawl at any 

 considerable depth, and the net was usually got in only at 

 nightfall. The ship, when dredging, used to lie rolling about 

 all day drifting along with the wind and dragging the dredge 

 slowly over the bottom. " At last, in the afternoon, the 

 dredge-rope was placed on the drum, and wound in for three 

 or four hours, sometimes longer. Often the rope or net, 

 heavily weighted with mud, hung on the bottom, and there 

 was great excitement as the strain gradually increased on 

 the line. On several occasions the rope broke, and the end 

 disappeared overboard, three or four miles of rope and the 

 dredge being thus lost. At first, when the dredge came up, 

 every man and boy in the ship who could possibly slip away, 

 crowded round it, to see what had been fished up. Gradually, 

 as the novelty of the thing wore off, the crowd became 

 smaller and smaller . . . and as the same tedious animals 

 kept appearing from the depths in all parts of the world, the 

 ardour of the scientific staff even abated somewhat, and on 

 some occasions the members were not all present at the critical 

 moment, especially when this occurred in the middle of 

 dinner-time, as it had an unfortunate propensity of doing. 

 It is possible even for a naturalist to get weary of deep-sea 

 dredging. Sir Wyville Thomson's enthusiasm never flagged, 

 and I do not think he ever missed the arrival of the net at 

 the surface." ^ 



The conditions under which life exists in the deep sea are 

 very remarkable. The pressure due to the weight of water 

 is enormous, and amounts roughly to a ton on the square 

 inch for every thousand fathoms ; so that at 5,000 fathoms 

 the pressure is about five tons, that is, between seven and eight 

 hundred times as great as the 15 lb. on the square inch we 

 are accustomed to at sea-level. On one occasion we are told 

 that Mr. Buchanan, the chemist to the expedition, hermeti- 



^ Notes of a Naturalist on the " Challenger," p. 501. 



