1 92 THE BORDERLAND OF SCIENCE. 



no way whatever of forming the vaguest idea as to 

 the possible occurrence of star-showers belonging to 

 any given system. There is scarcely a night in the 

 year when a display of meteors may not occur a 

 display belonging to a recognised meteor stream, but 

 to one whose period has not been determined. 



The very fact that astronomers recognise an associa- 

 tion between meteors and comets shows that a long 

 interval must elapse before the periods of most of the 

 meteor systems can be determined. For we see that 

 the November meteors exhibit their great displays at 

 intervals of about thirty-three years, this being the 

 period of the comet they belong to ; and the August 

 meteors have probably an interval of about 150 years, 

 corresponding to the period of the comet of 1862 ; but 

 many of the comets observed by astronomers have 

 periods measured not by decades but by centuries, 

 and even by thousands of years. 



It however chances that, in a quiet sort of way, as- 

 tronomers had discussed the possible occurrence of a 

 star-shower during the last week in November ; and as 

 we shall presently see, the shower which actually oc- 

 curred was the one thus looked for. The circumstances 

 are somewhat remarkable. 



There is or, perhaps we should rather say, there 

 was a celebrated comet called Gambart's by the 

 French, but by all other astronomers named after the 

 German astronomer Biela. This comet was first fairly 

 discovered in February, 1826, though it had been seen 

 in the years 1772 and 1805. It was found to revolve 



