154 



THE WATERS OF THE EARTH 



water and mark the depth to which it sinks. If sea water cannot 

 be obtained, dissolve in a pint of fresh water about 15 g., or half 

 an ounce, of salt. This will give the water about the same amount 

 of dissolved solid material as sea water has. About how much 

 more of its length does the hydrometer sink in fresh water than 

 in sea water? Will a piece of ice project more out of salt water 

 than it would out of fresh water ? 



On account of the materials dissolved, sea water weighs 

 more than fresh water, or has a greater specific density. 

 Floating bodies therefore have less of their volumes sub- 

 merged in sea water than in fresh water. A cubic foot of 

 sea water weighs over 64.25 pounds, whereas a cubic foot 

 of fresh water weighs only about 62.5 pounds. The specific 

 densitv of sea water is about 1.03. 



Ocean Depths. The greatest depth thus far found in 

 the ocean is over six miles. This was found in the Pacific 



Ocean near the Philippine 

 Islands, 

 depth 



3W4 Ft -SEA LEVEL. 





The greatest 

 in the Atlantic 

 Ocean thus far discov- 

 ered is a little over five 

 miles at a point north 

 of Porto Rico. The 

 average depth of the sea 

 is probably about two 

 and one half miles. 



Although the pressure 

 at the bottom of the 

 ocean must be tremendous, yet so incompressible is water 

 that a cubic foot of it weighs but little more at the bottom 

 of the sea than it does at the top. Thus a body which 

 readilv sinks will in time reach the bottom, no matter what 



MOUNT EVEREST 



As it would appear if placed in the 

 deepest part of the sea. 



