H. A. Newton— Biela Meteors of Nov. 27th, 1885. 419 



one-tenth of the observed zenith distance of the radiant. When the 

 radiant is near the horizon the change is somewhat greater 

 than one-tenth of the zenith distance: 



The radiant was to the east of the greater number of ob- 

 servers until the shower had nearly ceased, and the correction 

 would be generally under 2°, though in some cases exceeding 

 that amount. 



A second correction to the observed place of the radiant is 

 required by reason of the motion of the observer due to the 

 rotation of the earth on its axis. This correction must be ap- 

 plied before the observed places can be compared with each 

 other, or with a radiant deduced from the orbit of a comet. 

 For the Biela meteors this may be easily shown to be about 

 l 0, OXsine of the arc from the east point of the heavens to the 

 radiant and is to be applied to increase that arc. It is nearly 

 constant for the European observations in the table. 



These two corrections do not appear, however, to bring the 

 scattered radiant positions any nearer together. We cannot, 

 therefore, regard the earth's attraction and rotation as having 

 much to do with their wide distribution over the constellation 

 from which the meteors proceed.* 



The luminous portions of meteor tracks are usually to the 

 eye arcs of great circles. It is only in rare cases that the path 

 appears curved. The luminous paths of the meteors were 

 therefore straight lines, but were not parallel lines, for had they 

 been parallel, the radiant should be a mere point, and not an 

 area. How much they deviated from parallelism it is not easy 

 to determine with exactness. That their directions differed 

 from the average direction of the group by angles which for a 

 considerable fraction of the whole number of meteors amounted 

 to several degrees, seems a proper and necessary inference from 

 the wide scattering of the radiant points as described by the 

 observers and represented in the figure on page 417. Mr. 

 Denning says (Mon. Not. E. A. S., xlvi, p. 69), " The area of 

 radiation must have been fully 7° in diameter to accommodate 

 the discordances in the flights. The center was at 24°, +44°, 

 but I saw several very short paths from a point south of y 

 Andromedse. I noted many of the meteors with the utmost 

 care in order to assure myself of the diffuseness of radiation, 

 and it was found impossible to get a sharply defined position. 



* Since writing the above, Professor Foerster's paper, in No. 2720 of the Astr. 

 Nachr. containing a discussion of thirty-two assiguecl positions of the radiant in 

 this shower has been received. He applied the above two corrections to the 

 observed places, and gives the reduced R. A. and declination of each assigned 

 radiant. If the means of the observed R. A.'s or declinations be taken, and their 

 deviations from the observed added together (neglecting sign), the sum is 97° -, 7. 

 But if the corresponding sum of differences be taken for his reduced places, the 

 sum is 98° - 8. In other words, the radiants are equally scattered before and after 

 correction. 



