ASTRONOMY AND METEOROLOGY. 379 



with those bodies, not hitherto noticed, in favor of the theory that they are 

 identical in nature and origin. After stating some arguments against the 

 theory of the atmospheric origin of aerolites, Mr. Greg proceeded to give an 

 abstract of some results he had lately obtained in analyzing a very complete 

 catalogue of aerolite falls. It would appear that since A. D. 1500, there are 

 175 authenticated instances of falls of aerolites, the month of whose fall is 

 known, the number for each month being as follows : For January, 9 ; 

 February, 15; March, 17; April, 14; May, 15; June, 17 falls first half of 

 the year, 87 falls; July, 18; August, 15; September, 18; October, 14; 

 November, 16; December, 7 falls second half, 88 falls. Giving an average 

 of 14-6 for each month. The most important tiling to notice is the small 

 number of aerolites registered for the months of December and January, and 

 the comparatively large number for June and July. The former two showing 

 but 16 instances of falls, the latter two 35, or more than double. Now, 

 granting that these aerolites, or meteorolites, belong to the system of the 

 asteroids, having orbits therefore whose mean distance is superior to the 

 earth's orbit, it is certainly reasonable to conclude that it is when the earth 

 is farthest from the sun, i.e. at her aphelion, that the meeting with aerolites 

 is rendered most probable. This is what would appear to be really the case, 

 for the earth is at her greatest distance from that luminary on the side of the 

 summer solstice, i.e. in June and July, precisely the months shown to be 

 most abundant in aerolites. Mr. Greg then referred to a recent number of 

 the Comptes Rendus, in which there is a paper by Le Terrier on the asteroids. 

 M. Le Yerrier shows by calculation that the sum of the mass of the frag- 

 mentary planets, called asteroids, cannot exceed one-fourth of the earth's 

 mass ; and also shows it probable that their mean mass or system is at its 

 perihelion, and consequently nearest the earth, at the time when the earth 

 herself is on the side of the summer solstice. This would appear again con- 

 firmatory of the theory that aerolites are the minute outriders of the as- 

 teroids. There would appear to be also further evidence, though of another 

 kind. It has been supposed that some of the larger asteroids have irregular 

 and angular surfaces, which is precisely the case with the majority of the 

 meteoric stones which fall to the earth. Again, taking the average specific 

 gravity of aerolites at 3 '0 (they vary from 1-7 to 3 -9), further indirect evidence 

 is afforded as to their position with regard to distance from the sun, and, 

 taking water as TO, the following table shows the relative densities of several 

 of the planetary bodies, following the order of their distances from the sun: 

 Mercury, 157; Venus, 5'9 ; Earth, 5'6; Mars, 5'2; Aerolites, 3'0; Aste- 

 roids, (?) ; Jupiter, 14. Another circumstance relating to aerolites which was 

 alluded to by Mr. Greg, was the periodicity of those bodies, and he mentioned 

 more particularly the 19th of May, 29th of November, 13th of December, 15th 

 to 19th of February, and 26th of July, as being aerolite epochs, aerolite falls 

 having been recorded on the following days : February 10, 10, 13, 15, 15, 

 15, 18, 18, 18, 19, 19, 25, 27, 27; May 9, 10, 17, 17, 17, 18, 19, 19, 20, 22, 

 26, 26, 27, 28; July 3, 3, 4, 7, 8, 12, 14, 17, 18, 22, 24, 24, 26, 26, 26, 30; 

 November 5, 7, 11, 13, 17, 20, 23, 25, 27, 29, 29, 29, 29, 30, 30; December 

 11, 13, 13, 13, 13, 13, 14. In referring, however, to the epochs most remark- 



