452 SCIENCE PROGRESS 



The facts proving stationary radiation were embodied in a 

 paper published by the Royal Astronomical Society {Monthly 

 Notices, vol. x), and though the observations have not been 

 refuted, no satisfactory explanation of the curious fact has 

 ever been advanced. Many ingenious attempts have been made, 

 either partly or wholly to accommodate the long-enduring 

 showers, but without success. 



When the first endeavours were made to match Comet 1861 I 

 with the Lyrid meteor system, the resemblance of orbit was 

 not very marked. This was, however, owing to a faulty posi- 

 tion given for the radiant. From later observations, the radiant 

 was proved to be precisely in the point which had been 

 calculated for meteors directed from the comet. 



The heights of the swift-moving meteors such as the Leonids 

 and Perseids is proved to be decidedly greater than that of the 

 slow-moving meteors. Perseids and Leonids commence their 

 luminous careers at about 82 miles and end them at 54 miles. 

 The Leonids move with a theoretical velocity of 44 miles per 

 second, whilst that of the Perseids is 38 miles per second. The 

 latter are usually about 2 miles lower in the air than the former. 

 Slow-moving fireballs often penetrate to within 25 or 30 miles 

 of the earth's surface ; but I have never found a well-observed 

 meteor of the Leonid type fall to within an altitude of 40 

 miles. The Orionids of the October display are of smaller 

 type than the Perseids ; but they have a radiant essentially 

 different — for it appears to retain an immovable place between 

 October 9 and 29. 



It is a well-ascertained fact of recent years that nearly all 

 the large fireballs have slow motions, and come from western 

 radiants ; thus they are overtaking the earth in her orbit, and 

 revolving in direct orbits like the periodical comets of the 

 Jovian family. There are many fireballs from radiants near the 

 Zodiac ; but the rule is not absolute, these bodies being some- 

 times directed from regions widely removed — proving that the 

 inclinations of their orbits are occasionally considerable. 



Photography has played a great part in assisting astro- 

 nomical discoveries, and in allowing us to attain a higher degree 

 of accuracy in the representation and measurement of celestial 

 objects ; but it has practically failed in the meteoric field. The 

 fugitive durations prevent their being impressed on the plates, 

 except in the case of the more brilliant specimens. It was 



