PROGRESS OF MODERN ASTRONOMY 



and decay which seem everywhere to represent the 

 immutable order of nature. 



COMETS AND METEORS 



Until the mathematician ferreted out the secret, it 

 surely never could have been suspected by any one that 

 the earth's serene attendant, 



" That orbed maiden, with white fire laden, 

 Whom mortals call the moon," 



could be plotting injury to her parent orb. But there 

 is another inhabitant of the skies whose purposes have 

 not been similarly free from popular suspicion. Need- 

 less to say I refer to the black sheep of the sidereal 

 family, that "celestial vagabond" the comet. 



Time out of mind these wanderers have been sup- 

 posed to presage war, famine, pestilence, perhaps the 

 destruction of the world. And little wonder. Here is 

 a body which comes flashing out of boundless space into 

 our system, shooting out a pyrotechnic tail some hun- 

 dreds of millions of miles in length; whirling, perhaps, 

 through the very atmosphere of the sun at a speed of 

 three or four hundred miles a second ; then darting off 

 on a hyperbolic orbit that forbids it ever to return, or 

 iliptical one that cannot be closed for hundreds or 

 thousands of years ; the tail meantime pointing always 

 away from the sun, and fading to nothingness as the 

 1 voyager recedes into the spatial void whence it 

 came. Not many times need the advent of such an ap- 

 parition coincide with the outbreak of a pestilence or 

 the death of a Caesar to stamp the race of comets as an 



