A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 101 



tions are calculated to add to the precision -with which, it will in future be 

 desirable to fix the epochs and positions of these radiant-poiiits. When the 

 epochs and positions of the different general radiant-points of shooting-stars 

 are more exactly circumscribed, it may be reasonably expected that fireballs 

 and meteorites wiU be shown to belong, hke shooting- stars, to meteoric 

 showers. 



The results arrived at independently by Professor Heis, of Miinster, are in 

 general strongly corroborative of those obtained by Mr. Greg, of Manchester, 

 though in certain cases the latter exhibits radiants not given by the former, 

 and vice versa. Professor Heis, however, has somewhat arbitrarily divided 

 his meteor-showers and radiants into bi-monthly divisions, and has thus 

 occasionally presented the same shower with a number of radiants more or 

 less closely aUied to each other. 



Mr. Greg has endeavoured to give as nearly as possible the precise dura- 

 tion and limit of each shower, as well as the average position of its connected 

 radiant. 



The general results may be thus summed up, with a tolerable degree of 

 certainty, as regards the meteor-sliowers. 



They appear to endure for almost any period, from twenty-four hours to 

 eight or possibly ten weeks, differing from one another in richness or intensity 

 of display. In some there appears to be a tendency to maximum display 

 on particular days, as for example xlvii., lasting from November 26th to De- 

 cember 30th ; but the most abundant display occurs from December 9th to 

 13th. In others no such maximum can be perceived. Their number, of 

 fully fifty as yet ascertained, will probably not be much exceeded, unless 

 by short-lived showers, and by others whose radiants culminate just before 

 dawn. There is no confusion or chance in their return, but, on the contrary, 

 the showers arc very regularly reciu'rent every year, and, allowing a radiant- 

 region of 10° to 15° in diameter for each, the so-called " sporadic" meteors 

 wiU become extremely scarce, now that the principal showers and their 

 radiants have been pointed out. A well-marked instance of long persistence, 

 and remarkable for having its radiant very small and fixed, is the shower of 

 August 6th to September 10th, no. xxix. The great majority have, at the 

 present time, been as clearly defined (as regards the time of their occurrence, 

 duration, and positions of their radiants) as is the case with the older and 

 better-knowia showers of August and Ifovember, On the average of many 

 years, the radiant-regions of a few are, however, still very extensive. In all, 

 a plane, oval, or double-headed region of radiation appears to represent the 

 conditions of the showers more correctly than a point. This elongation of 

 the radiant-region is in most cases perpendicular to the ecliptic, or parallel 

 to the via lacfea, in or near which the greater number of the radiants in the 

 latter half of the year are placed. The meteors of particular showers vary 

 in their distinctive characters, some being larger and brighter than others, 

 some whiter, some more ruddy than others ; some swifter, and drawing after 

 them more persistent trains than those of other showers. Their connexion 

 with the epochs and directions of large meteors stUl remains to be esta- 

 blished. 



