The Ocean Bottom 31 
rocks from a distant continent carried there on a melting ice- 
berg, and sand dust from the Sahara. 
The pressure in the ocean deeps is over 10,000 pounds per 
square inch. Although pressures of this amount are tremen- 
dous, physicists at Harvard have produced far greater pres- 
sures in their laboratories. 
The great pressure at these depths compresses the sea 
water somewhat, increasing its density. However, the in- 
crease is not significant and cannot prevent heavy objects 
from sinking all the way to the bottom. Sailors are fond of 
arguing about how far things will sink, whether it concerns a 
sinking wreck or a burial at sea. Let it be said, therefore, once 
and for all, that if an object is heavy enough to sink beneath 
the surface, it is heavy enough to sink all the way down. 
There is no reason to suppose that the derelicts of bygone 
days, and the corpses of shipwrecked sailors are floating 
about in some eerie intermediate zone of the ocean between 
top and bottom. 
Large objects of similar density tend to sink faster than 
small ones! This is because they offer less resistance in pro- 
portion to their weight, than do small ones. A grain of coarse 
sand would fall a foot through water in about one second, 
whereas fine clay particles would take half a year to settle the 
same distance. At this rate it must have taken the fine clay 
particles from the deepest ocean deposits 15,000 years to sink 
from the surface to the bottom, yet even these particles reach 
the bottom. 
