Z4 IN STARRY REALMS. 



hundred thousand miles and its length about fifteen thoti* 

 sand times as great. Such is the shape of the mighty 

 shoal which has, for the past thousand years, given us 

 perennial displays of Leonids. It is at this moment and 

 at every moment pursuing a mighty path through space. 



The matter is so important that I venture to repeat here 

 an illustration which I have already given in " Star Land." 

 Think of a racecourse which is oval-shaped, or elliptical, 

 as it should be more properly called. Think of a number 

 of men who started together on that course to run a race. 

 Let us further suppose that the number of competitors is 

 a large one, and that they have to complete a considerable 

 number of rounds ere the winning tape will be stretched 

 across the track. We should then find that the shape of 

 the group of athletes was continually being extended. "We 

 should also find that some few exceptionally good runners 

 were able to draw ahead in advance of the main body. No 

 doubt a large field would also contain some tardy runners 

 who would inevitably be left far behind, so that as the 

 successive rounds were completed we should see that the 

 first were actually overtaking the last, and thus gaming 

 an entire circuit. After a time a condition of the field 

 would be reached in which the main body of average run- 

 ners was in a stream occupying a small fraction of the 

 entire course, while the rest of the track would be dotted 

 here and there with those competitors who were either 

 exceptionally swift or exceptionally slow. 



Submit this illustration to an imaginary species of 

 transformation and of enlargement. Instead of the small 

 course a fraction of a mile in circumference, let us think 

 of a course still oval in shape, but many hundreds of mil- 



