A CATALOGUE OF OBSERVATIONS OF LUMINOUS METEORS. 131 



Their average velocity, greater than that of the earth, implies that the 

 meteoroids are not closely grouped about the earth's orbit. That they are 

 grouped according to some law is, however, altogether probable. 



1st. They may form a number of rings, like the August ring, cutting or 

 passing near the earth's orbit at many points along its track. The sporadic 

 shooting-stars may be outliers of such rings. 



2nd. They may form a disk in or near the plane of the orbits of the 

 planets. 



3rd. They may be distributed at random like the orbits of the comets. 



According to the first of these suppositions there should be a succession of 

 radiants corresponding to the several rings. Dr. Heis and Mr. B,. P. Gre<* 

 believe that they have detected such a series. Continued observation di- 

 rected to this end will probably decide whether the meteoroids belong entirely 

 or mostly to rings. 



The meteoroids neither belong exclusively, nor even largely to a disk, or to 

 a lenticular-shaped group about the sun, like that which the zodiacal light is 

 often supposed to indicate. The orbits of their rings are not in general cir- 

 cular, as may be inferred from their great velocity, but resemble more the 

 orbits of the comets. Finally, they cannot be regarded as the fragments of 

 former worlds, but may rather be described as the materials from which new 

 worlds are forming. (See pp. 135, 136). 



(3.) Streaks, Detonations, ifcc. of Meteors (Vienna Acad. Sitzungsber., 



1864, November 10th). 



From a carefully revised catalogue of 2950 meteors in the northern hemi- 

 sphere, the percentages of detonating, caudate, and aerolitic meteors are sepa- 

 rately determined by Dr. Julius Schmidt for every month. The percentage 

 of detonating meteors in August is three times less than in March. The 

 greatest percentage of aerolitic meteors is observed in May, when the per- 

 centage of caudate meteors is the least. On the average of the whole year, 

 different coloured shooting-stars are observed in the following proportions :— 



White 75-8 per cent. Eed 5-7 per cent. 



Yellow ..15-9 „ Green ..2-6 „ 



The average durations in seconds, for the different colours, are as follows : 



White meteors 0-775 sec. Red meteors 1-905 see. 



Yellow meteors ..0-921 „ Green meteors ..3-127 sees. 



If the meteor of the 18th of October 1863 is omitted from the thirty- 

 two green meteors, included in the last average, the average duration of the 

 remaining thirty-one green meteors is 2-584 sees. 



(4.) Meteorological Observations at the Flagstaff Observatory, Melbourne 



Victoria, 1859 to 1862, p. 137. 

 From the mean of 1428 meteors observed in 668 hours, in three years 

 l)r. Neumayer concludes the following hourly numbers of meteors at Mel- 

 bourne, in the different months : — 



January 2-1 April 1-4 July 2-7 October 2-9 



February 1-9 May 1-9 August 2-7 November 1-7 

 March 1-7 June 2-8 September 2-5 December 2-8 



