HALLEY'S COMET 493 



traditions of the respectable solar family circle and pursue the 

 even tenor of their way round their parent the sun (be it shy 

 Mercury; Venus, now bashful and modest; ourselves, the Earth; 

 ruddy Mars, with his puzzling canals ; giant Jupiter ; Saturn, 

 the gem of the family ; or the latest arrivals, those slow-coaches 

 Uranus and Neptune). Compared with these steady old files, 

 comets are wild, impetuous fellows who lead restless, irregular, 

 roving lives. For them the humdrum family existence has no 

 attraction ; the spirit of adventure fascinates them and impels 

 them to explore the starry depths of the universe. They may 

 be compared with the prodigal son, for this life of dissipation 

 wastes their substance. Like him they return home, but in their 

 case it is only a flying visit, as they immediately hurry off again 

 on a fresh voyage of adventure, to return again and again after 

 approximately the same period of absence. Each visit shows 

 that the life the}^ lead is telling on them: they are not so bright ; 

 their clothes show signs of wear and tear ; still they continue to 

 pursue their reckless, roving life until, utterly exhausted, their 

 dissolution comes about, and if they do revisit the family they 

 are so shrunk, changed, and disintegrated as to be no longer 

 recognisable, though their tombstones are placed in the heavens 

 in the shape of meteoric swarms which serve to mark out the 

 paths of their individual journeys. 



This life-history of a periodic comet was unknown two 

 hundred years ago. It would have been hardly possible then 

 for any but astronomers to have mentioned the word " comet " 

 without experiencing a thrill or a shudder. In all ages comets 

 have been superstitiously regarded as heralds, and even as the 

 actual causes, of strange or disastrous events, plague, famine, 

 war, or the death of princes. In the opening scene of King 

 Henry VI., Shakespeare makes the Duke of Bedford, Regent 

 of France, say in reference to the death of Henry V. : 



" Hung be the heavens with black, yield day to night! 

 Comets, importing change of times and states, 

 Brandish your crystal tresses in the sky." 



Again, in Julius Ccesar occur the well-known lines : 



" When beggars die there are no comets seen, 

 The heavens themselves blaze forth the death of princes." 



A quaint old book, published in 1549, called The Complaynt 

 of Scotland, speaking of " the Star called a Comet," says : 



