452 The November Shooting Stars. 



of November , or at least the vast majority of them, describe ap- 

 parently, arcs of great circles, passing through or near 7 

 Leonis. No matter what the situation of that star with respect 

 to the horizon, or to its east or west points may be at the 

 time of observation, the paths of the meteors all appear to 

 diverge from that star." 



The exact position in the heavens from which the meteors 

 appear to radiate, technically known as the " radiant point," 

 is one of the subjects to which the attention of observers has 

 been of late years much directed, and the spot which it occu- 

 pies in Leo has probably been ascertained with great precision 

 on the present occasion. 



And now to sum up the theory, so far. We suppose the 

 earth in its orbit, A, around the sun, to encounter a ring of 

 meteors, B, at the point marked " Nov." There, and there 

 only, we are led to believe, the orbit intersects the ring. At 

 the opposite point, marked "May," the ring falls a little 



within the orbit of the earth, 



instead of cutting through it. 



A display of the meteors in this 



ring can therefore occur only 



in November. Now if the ring 



were uniform, i. e., an unbroken 



stream of meteors through its 



whole circle or ellipse,* the 



may. earth's encounter with it would 



take place every revolution — 



we should see an exactly similar star-shower every November 



13 or 14. 



But " if the ring be broken," — here again I quote Sir John 

 Herschel — "if it be a succession of groups revolving in a 

 period not identical with that of the earth, years may pass 

 without a rencontre; and when such happen, they may differ 

 to any extent in their intensity of character, according as richer 

 or poorer groups have been encountered." A blank part of the 

 ring will occasionally occupy the point of intersection just as 

 the earth ai-rives there — then there will be no November 

 meteors visible that year. Again, a rich part of the stream, 

 the jewel of the ring, of which we shall presently have much to 

 say, ma}'- come to the point of intersection when the earth is 

 there — then we shall have a glorious display, as in the year 

 1866. 



Or, let us suppose we meet a thinner part of the ring, then 

 we have an ordinary November star-shower, such as those 

 which occurred in 1822, 1823, 1832, 1$33, etc.; or, to take 



* It is believed to be nearly circular. 



