136 A NATURALIST ON DESERT ISLANDS. 



their way about or capturing prey. But this light cannot 

 have much carrying power, beyond the more or less 

 immediate vicinity of the fish or beast concerned ; so that 

 the latter 's range of vision is probably much contracted. 

 And however long its range of vision might be, it would 

 be no better off, for there would be nothing to see, but the 

 same dreary circle of faintly illuminated gloom, the same 

 everlasting monotony of the drab-colonred ooze at the 

 bottom. 



But if we may be further permitted to wander from 

 the immediate subject of " What Swan Island really is," 

 let us quote a few examples to justify our words. 



Here is how Agassiz, who worked in this very sea, 

 .graphically describes the chilliness of these great depths, 

 sach as surround Swan Island. " The great cold of the 

 bottom water of the ocean, even in the Tropics, is best 

 brought home to those who have examined the contents 

 of a haul of the trawl. The bottom ooze is intensely 

 cold ; and it is a strange sensation, Avhile one's back is 

 hroiling beneath a tropical sun, to have one's hand nearly 

 frozen from the stiff cold mud or ooze that one is compelled 

 to handle while assorting the contents of the trawl." 



Listen again, to how Mr. Alcock, in his most interesting 

 book, " A Naturalist in Indian Seas," makes us realize 

 the awful pressure to which deep-sea animals are subjected. 

 " We had sent down in the trawl bag an untouched bottle 

 of Bass's beer ; and when it came up, though the capsule 

 and wires were intact, the cork was so much compressed, 

 that it rattled in the neck of the bottle, and the bottle 

 itself contained a mixture of beer and salt water. 



" The pressure at a depth of 1,439 fathoms (8,634 feet), 

 amounting to nearly two tons on the square inch (italics 

 ours), had been sufficient to turn the cork into a pellet 

 of hard wood, and to force the sea water under the capsule, 

 and so between the mouth of the bottle and the shrunken 

 €ork." 



Agassiz lowered, on one occasion, a bottle of champagne 

 to a depth of 2,400 fathoms, with much the same results. 



