PARABOLIC ORBITS OF METEOR STREAMS 469 



made the connection even vaguely probable. Denning in his General 

 Catalogue on p. 223, mentions that his group CCLVIII, called by him 

 Aquarids, are probably connected with Halley's Comet. On p. 283 were 

 given the 8 radiants, on which his conclusions must be based. Only two 

 of these were deduced from observations of a single night; the others 

 therefore are really useless for the question involved. Whether he made 

 any computations or not is not stated, but the presumption is that he is 

 repeating the conclusion of Prof. A. S. Herschel. In any case were orbits 

 computed for these eight radiants they would give hopelessly discordant 

 results, and hence could prove nothing. 



Various attempts had been made here previous to 1910 to observe these 

 meteors but with poor success due to bad weather, moonlight, etc. It 

 was not until, 1910, May 4, when the author was at the Lick Observatory, 

 that a good radiant was secured for the rj Aquarids. 



Another excellent radiant was obtained in 1910, May 11, and the para- 

 bolic elements were at once computed and the results published in the 

 Publications of the Astronomical Society of the Pacific for June, 1910. The 

 elements of the comet's orbit were placed side by side with those of the 

 meteors, and the connection between them first definitely proved in this 

 paper, so far as is laiown to the author. 



Further papers have been published, as more data were acquired, the 

 last and most important appearing in A. J. No. 640, p. 128-130. 



In table IV of the present paper the elements based on all eight radiants, 

 secured from 1910 to 1913 inclusive, are given. They are calculated in two 

 ways: First, by assuming the meteors had the parabolic velocity, which is 

 the assumption made for all the orbits in table II, secondly that they have 

 the same major-axis as Halley's comet, and are moving in elliptical orbits. 

 In spite of the fact that the comet's orbit never comes nearer than 4,000,000 

 miles of the earth's orbit and that consequently the orbits of meteors 

 we meet can not be absolutely identical with the comet's path, yet the 

 agreement of the elements are so close for both cases that no doubt can 

 remain that these meteors were originally intimately connected with the 

 comet. > 



It is of great interest to see how far from the comet's orbit some of these 

 meteors actually move — ^namely as much as 11,000,000 miles for those of 

 1910, May 11. It should likewise be noted that the meteors were still 

 coming in 1913 in nearly as'great nimibers as in 1910, when the comet was 

 nearest the earth. We can have no better example of the process of slow 

 dissolution of a large comet into a meteor stream, and hence meteor ob- 

 servers are urged in future years to pay more attention to these meteors, 

 which seem so strangely neglected until verj^ recentl5^ 



