32 THE DEPTHS OF THE SEA. [CHAP, I. 
according to their specific weight: skeletons of men, 
anchors and shot and cannon, and last of all the 
broad gold pieces wrecked in the loss of many a 
galleon on the Spanish Main; the whole forming a 
kind of ‘ false bottom’ to the ocean, beneath which 
there lay all the depth of clear still water, which was 
heavier than molten gold. 
The conditions of pressure are certainly very extra- 
ordinary. At 2,000 fathoms a man would bear upon his 
body a weight equal to twenty locomotive engines, each 
with a long goods train loaded with pig iron. We are 
apt to forget, however, that water is almost incom- 
pressible, and that therefore the density of sea-water 
at a depth of 2,000 fathoms is scarcely appreciably 
increased. At the depth of a mile, under a pressure 
of about 159 atmospheres, sea-water, according to the 
formula given by Jamin, is compressed by the 34; of 
its volume; and at twenty miles, supposing the law of 
the compressibility to continue the same, by only + of 
its volume—that is to say, the volume at that depth 
vould be £ of the volume of the same weight of water 
at the surface. Any free air suspended in the water, 
or contained in any compressible tissue of an animal 
at 2,000 fathoms, would be reduced to a mere fraction 
of its bulk, but an organism supported through all its 
tissues on all sides, within and without, by incom- 
pressible fluids at the same pressure, would not 
necessarily be incommoded by it. We sometimes 
find when we get up in the morning, by arise of an 
inch in the barometer, that nearly half a ton has been 
quietly piled upon us during the night, but we expe- 
rience no inconvenience, rather a feeling of exhilara- 
tion and buoyancy, since it requires a little less exer- 
