190 HALLEY'S COMET. 



Among the circumstances attached to the comet, of Halley, which will at- 

 tract attention, is the fact of its gradually decreasing brightness. \Ye have seen J 

 that oh some occasions of its recorded visits at remote periods, it pre-sented an I 

 appearance which filled the people with terror. Every one knows how insig- 

 nifieant an object it was on its return in 1835. If it be true that comets thus 

 waste themselves away, new data will be afforded to aid in forming a physi- 

 cal theory for their explanatioa. 



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