6 that' 



8, 9, 10, and which, instead of 

 allowing the lead, 10, to reach 

 the bottom, 7, bear it away. The 

 great density of deep waters also 

 prevents the lead sinking. When 

 the line, 9 9, is first thrown ont, 

 the lead, 10, sinks rapidly ; but 

 upon reaching great depths it 

 will scarcely sink further, on ac- 

 count of the great pressure of the 

 water. Adhesive matter is fre- 

 quently attached to the lead, 

 which, taking hold of some frag- 

 ments of the bottom, indicates 

 its nature. The results of such 

 measurements of depths, and in- 

 dications of the nature of the 

 bottom, are soundings, which are 

 carefully entered in the ship's 

 log-ooolcs. If the sea were to be 

 dried up, there would appear vast 

 regions of sandy deserts, bound- 

 less ocean prairies, lofty moun- 

 tains, deep valleys, open plains, 

 narrow ravines, mountains with 

 broad table-lands, high cliffs with 

 dark caverns, immense abysses, 

 and all the varying features of 

 the earth's surface, marked in 

 bolder and more romantic cha- 

 racters by the powerful action ot 

 water since the world's formation. 



The ocean is tenanted with 

 living creatures, presenting a won- 

 derful variety of forms, most of 

 them useful to man, and many of 

 the various species abounding in 

 countless myriads. The Green- 

 land whale (JBalcena mysticetus) 

 11, is the giant of the arctic seas. 

 There great numbers of them 

 congregate, and frolic in the 

 waters ; some darting along the 

 surface, others diving, and then 

 leaping into the air, others sport- 

 ing, and lashing the water into 



's it ; 



foam with their powerful tails; 

 all of them discharging volumes 



114 



of water through their blowers, 12, 

 from which they filter the minute 

 shrimp-like Crustacea, and jelly- 

 like Medusce, upon which they 

 feed. Creatures of amphibious 

 habits live upon the shores of the 

 polar seas, or tenant the vast 

 worlds of ice which there exist, 

 13. Among these, the most re- 



us. 



markable is the walrus* (Tri- 

 checus Rosmarus), 14, familiarly 

 called the " sea-horse," " sea- 



• The walrus is not an amphibious animal. Strictly 

 speaking, no animals are amphibicrun but such as pos- 

 sess both lungs and gills. Yet many animals, such as 

 walruses, seals, otters, beavers, etc., have amphibious 

 habits, though they are not amphibious. 



