THE OLIVE LEAF. 



changed into coal-beds under the earth. In this 

 wonderful way two great results were accomplished at 

 the same time and by the same means ; the atmosphere 

 was purified and made fit for the breathing of man, and 

 animals useful to man, and vast stores of fuel were pre- 

 pared to enable future generations to subdue the earth 

 and spread over it the blessings of civilization. And 

 what the green leaves of the early geological forests did 

 for the primeval atmosphere of the world, the green 

 leaves of our woods and fields are continually doing for 

 our atmosphere still. They absorb the foul air caused 

 by the processes of decay and combustion going on over 

 the earth, and by the breathing of men and animals, and 

 convert this noxious element into the useful and beauti- 

 ful products of the vegetable kingdom. They preserve 

 the air in a condition fit for human breathing. Without 

 them, carbonic acid gas would soon accumulate to such 

 an extent that animal life would be impossible. There 

 would be no gaily- coloured blossoms to delight our 

 senses and stimulate the poetical side of our nature ; for 

 flowers are as pure breathers as man himself, and can- 

 not exist in a foul atmosphere. We little think when we 

 inhale the fresh air that its purity and healthfulness come 

 to us by the beautiful mission of the green leaf. Nor 

 have we only the green leaves of our own fields and woods 

 to thank for this blessing; the air that we breathe has 

 been purified for us, thousands of miles away, by the palms 

 of the south and the pines of the north, by the birches 

 of America, and the gum-trees of Australia. Nothing is 

 more wonderful in nature than the balance which is 



