THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



JUNE 1859. 



LXII. On the Pmods and Colours of Lumhious Meteors. 

 By J. H. Gladstone, Ph.D., F.R.S.* 



RECENTLY, on looking over the records of luminous me- 

 teors, several thoughts occurred to me which I believe are 

 new ; and some of them may be not unworthy of being brought 

 under the notice of those interested in the subject. 



Periodicity. — It is well known that showers of falling stars 

 and meteors occur at certain annual periods, and that the two 

 most remarkable of these are about August 10 and November 13. 

 They have been observed on these two dates, not only in our 

 own country, but on the continent of Europe, in America, and 

 in India ; and Humboldt has brought evidence to show that 

 August 10 has had a reputation for meteoric displays for several 

 centuries. It is not, however, every year that they are seen on 

 the dates in question, even though the sky be clear ; and they 

 are sometimes reported as occurring a day or two earlier or later. 

 This slight irregularity as to time may be one cause of their not 

 being observed during some years, for it is only when the star- 

 showers occur at night that they can be seen. A comparison of 

 more ancient observations throws additional light on the nature 

 of this periodicity. M. Chaslesf has drawn up a catalogue of 

 forty-six remarkable meteoric showers — or what are believed to 

 have been such — between a.d. 538 and a.d. 1 123 ; and here also 

 we find recurrent periods, but different from those at .present 

 observed. Not one instance is noted of a shower occurring any- 

 where about the middle of either August or November. From 

 the end of the sixth to the middle of the tenth century, but 



* Communicated by the Author, 

 t Comptes Rendus, March 15, 1841. 

 Phil. Mag. S. 4. Vol. 17. No. 116. June 1859. 2 D 



