50 NATURAL HISTORY READER. 



The leaves are thin, soft, and succulent, and of a bright 

 grassy green. 



5. The old tree seems to eschew all the indiscretions of 

 its youth. The stalk becomes round, the leaves elongate, 

 have a long petiole, and are placed alternate on the stalk. 

 But a greater change takes place in the character of the 

 leaf. It now becomes thick, leathery, dry, and of a bluish 

 green; and it turns so that one edge is up, exposing both 

 sides equally to the sunlight. To accomplish this change 

 of position, the petiole actually twists itself as if it knew 

 what it was about. The two sides of the leaf now become 

 alike both in organs and function. The ribs and veins are 

 alike prominent on each side, much as if the roof of a house 

 should have beams and rafters inside and out. Breathing 

 organs appear on both sides, and this is what gives to the 

 eucalyptus one of its most peculiar characteristics. Both 

 sides of the leaf work equally, and the tree becomes a 

 double-cylinder pum ping-engine, instead of a single one as 

 in other trees. 



G. The wood of the tree when freshly cut is soft ; but 

 the gum soon hardens, and it becomes well-nigh imperish- 

 able. The terrible ship-worm, which destroys most timber 

 exposed to its ravages, lets it alone, making it invaluable 

 for ship-timber, docks, and all marine structures. It is 

 proof against that fearful scourge of tropical regions, the 

 white ant ; hence, in India it is used for the sleepers of 

 railways and a multitude of other purposes. It furnishes 

 valuable timber to the wheelwright, carpenter, and cabinet- 

 maker. While the tree usually holds tenaciously to its 

 leaves, it readily sheds its outer bark, and such immense 

 pieces arc sometimes detached that the natives make a rude 

 hut from a single piece. It is specially valuable for shingles, 

 as it does not easily burn, and the gum makes it lasting 

 when exposed to the air. The bark of many species is ser- 

 viceable for paper-making. 



