THE STORY OF THE NOVEMBER METEORS. 45 i 



would add to this 7', Uranus would add 1' ; the effect of the earth 

 and other planets would be insensible. Adding these numbers to- 

 gether, the whole effect, according to Mr. Adams's computation, is 28', 

 almost exactly the same as the observed amount which had been 

 determined by Professor Newton, which was 29'. But, if the meteors 

 were in any of the other four possible orbits, the total amount would 

 never exceed 12'. Here, then, we have reached the final result : the 

 long orbit is the orbit of the meteors. This great discovery was pub- 

 lished in March, 1867. 



Meanwhile Signor Schiapparelli, of Milan, was laboring in another 

 direction. It was evident from the observations that the meteors were 

 drawn out into a long stream. What was the cause of this ? Signor 

 Schiapparelli pointed out that if a cloud of meteors were started under 

 conditions which are not quite the same, each meteor would pursue 

 its own orbit, which would differ from the others. If they were 

 treated almost exactly, although not quite, alike at starting, their va- 

 rious orbits would lie excessively close to one another, and would be 

 undistinguishable in most respects. But if there be any effect which 

 goes on accumulating from revolution to revolution, such an effect 

 would in the end become very sensible. And such an effect there is. 

 The periodic times differ a little in these different orbits. At the end 

 of the first revolution those meteors which have the longest periodic 

 times are the last to get back to the starting-point, and have, there- 

 fore, already fallen a little into the rear of the group, while those with 

 the shortest periodic time have gone a little ahead. At the end of 

 the second revolution the separation is doubled, and in each succes- 

 sive revolution the column is still more lengthened out. After a 

 sufficient number of revolutions it will be spread out over the whole 

 length of the orbit, and form a complete oval ring. This has not yet 

 happened to the November meteors, and we are thus assured that it 

 can not be any enormous period, speaking cosmically, since the time 

 when they first started on their present path. On the other hand, 

 the August meteors, which have returned punctually every year since 

 they were first observed, are probably a complete ring, and are at all 

 events of far greater antiquity than the November meteors. But they 

 are also, as might be expected, more scattered, so that the sprinkling 

 of meteors they discharge upon the earth as it passes through them 

 has nothing like the splendor of the great November shower. Signor 

 Schiapparelli also pointed out that there is a comet moving in the 

 track of the August meteors, and another in the track of the Novem- 

 ber meteors. We shall presently see the significance of this observa- 

 tion. 



The next great step was made by M. Le Verrier, the late Director 

 of the Paris Observatory. Acting on the suggestion made by Signor 

 Schiapparelli, M. Le Verrier pointed out that the orbit of the meteors 

 intersects the orbit of Uranus, as represented in the diagram. From 



