Masterpieces of Science 



time of beings capable of applying that metal 

 to the useful purposes which man makes it sub- 

 serve. The imagination suggests immediately 

 the existence of arts and sciences, trades and 

 manufactures, on that distant world. We 

 know how intimately the use of iron has been 

 associated with the progress of human civiliza- 

 tion, and though we must ever remain in ignor- 

 ance of the actual condition of intelligent beings 

 in other worlds, we are yet led, by the mere pres- 

 ence of an element which is so closely related to 

 the wants of man, to believe, with a new con- 

 fidence, that for such beings those worlds must 

 in truth have been fashioned. 



We know that the sun is the sole source whence 

 light and heat are plentifully supplied to the 

 worlds which circle around him. The question 

 immediately suggests itself Whence does the 

 sun derive those amazing stores of force from 

 whence he is continually supplying his dependent 

 worlds? We know that, were the sun a mass of 

 burning matter, he would be consumed in a 

 few thousand years. We know that, were he 

 simply a heated body, radiating light and heat 

 continually into space, he would in like manner 

 have exhausted all his energies in a few thousand 

 years a mere day in the history of his system. 

 Whence, then, comes the enormous supply of 

 force which he has afforded for millions on 

 millions of years, and which he will undoubtedly 

 continue to afford for at least as long a time as 

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