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THE POPULAR SCIENCE MONTHLY 



timent cannot suffer from the thoughts now occurring to us. We es- 

 tablish with such objects a relationship, I had almost said a friendship ; 

 they become, as it were, a part of ourselves, things essential to our 

 own existence ; and that deej) attachment we feel to the place of our 

 birth, or our home, finds its apology not alone in natural instinct, or in 

 acquired habits, but also in the highest philosophical considerations. 

 In imagination we might mark off groups in the two kingdoms which 

 are the fanciful representations or counterparts of each other. Per- 

 haps we men, who have to resist the storms of life, may have our 

 representatives in the rugged trees of the forest ; the ladies will cer- 

 tainly find, their antagonists among roses and other flowers. 



From what has been said, you will have gathered how important 

 is the part which oxygen plays in the scheme of N'ature. To it is com- 

 mitted the duty of destroying all animal races, and transferring the 

 parts of which their bodies are composed to plants. It begins to dis- 

 charge this function the moment we begin to breathe, pervading each 

 instant every part of our bodies, bringing on interstitial death, and the 

 continuous removal of particle after particle which it carries away. 

 For there is an incessant change in the substance of all living struct- 

 ures ; that which we are to-day differs from that of yesterday and 

 to-morrow, and this untiring agent is all the time at work, assaulting 

 and undermining, nor stopping its action with our dissolution, but 

 going with us into the tomb, until it has restored every particle back 

 to the air. Death is not, as the popular superstition says, a phantom 

 skeleton, nor, as the Asiatics tliink, a turbaned horseman, who pays 

 his sudden and unwelcome visits. He is this invisible principle in 

 the air which surrounds us, and which is in the very breath we 

 respire. 



If thus the duration of individuals and races is determined by the 

 two great systems of forces which have been combined into a self-act- 

 ing contrivance, it surely is one of the most interesting inquiries in 

 which we can engage, to find in what way so extraordinary a combi- 

 nation has been established. From those remote periods to which we 

 are able to trace the history of the earth, has the same kind of agency 

 prevailed, or have other laws and other self-acting contrivances been 

 resorted to in other times ? You see I here assume the doctrine of 

 the geological antiquity of the earth without any kind of hesitation. 

 During two centuries its spherical form was bitterly denied by many 

 very good and well-meaning men. But the truth at last prevailed. 

 And during the last fifty years its age has in a similar way, and on 

 similar principles, been contested. But this, like the former, is now a 

 settled question ; neither the one nor the other is any longer open to 

 debate. He who thinks the earth is only a few thousand years old, 

 simply knows nothing about the matter. He who denies its antiquity 

 will also probably deny its figure. 



I proceed, then, rapidly with the inquiry in which we are engaged, 



