PROGRESS OF MODERN ASTRONOMY 



been observed. In 1832 Biela's comet passed quite 

 near the earth, as astronomers measure distance, and in 

 doing so created a panic on our planet. It did no 

 greater harm than that, of course, and passed on its 

 way as usual. The very next time it came within tele- 

 scopic hail it was seen to have broken into two frag- 

 ments. Six years later these fragments were separated 

 by many millions of miles ; and in 1852, when the comet 

 was due again, astronomers looked for it in vain. It 

 had been completely shattered. 



What had become of the fragments? At that time 

 no one positively knew. But the question was to be 

 answered presently. It chanced that just at this period 

 astronomers were paying much attention to a class of 

 bodies which they had hitherto somewhat neglected, 

 the familiar shooting-stars, or meteors. The studies of 

 Professor Newton, of Yale, and Professor Adams, of 

 Cambridge, with particular reference to the great me- 

 teor-shower of November, 1866, which Professor New- 

 ton had predicted and shown to be recurrent at in- 

 tervals of thirty- three years, showed that meteors are 

 not mere sporadic swarms of matter flying at random, 

 but exist in isolated swarms, and sweep about the sun 

 in regular elliptical orbits. 



Presently it was shown by the Italian astronomer 

 Schiaparelli that one of these meteor swarms moves 

 in the orbit of a previously observed comet, and other 

 coincidences of the kind were soon forthcoming. The 

 conviction grew that meteor swarms are really the 

 debris of comets; and this conviction became a prac- 

 tical certainty when, in November, 1872, the earth 

 crossed the orbit of the ill-starred Biela, and a shower 



VOL. HI. 5 ce 



