ASTRONOMY AND METEOROLOGY. 373 



presumed, are stragglers from the ring or circular belt of stones re- 

 volving round the sun, and consist of individual blocks, which, durino- 

 their revolution, happen to come near enough to the earth to be 

 detached from their places by its attraction. Judging from the speci- 

 mens which visit our globe, these travelling stones must amount to 

 many millions,, since, in the aggregate, they are equal to one-tenth 

 of the earth's mass. It may be assumed that the orbit in which they 

 move has a different plane from that of the earth, and, if so, the fall 

 of aerolites can occur only at the points where the planes intersect, 

 that is, periodically, and twice a year at most ; while, as their orbit, 

 like the earth's, must be elliptical, and the ring of meteoric stones may 

 not be entire, but consist of detached portions, it is evident that 

 many years may elapse without the earth encountering one aerolite, 

 while, on othdfc occasions, it may encounter many in a single year. 



If M. Leverrier's conclusions are accepted, they extend the science 

 of astronomy in its more minute features, and make us acquainted, 

 by an indirect, but ingenious and refined process, with two multitu- 

 dinous systems of small planetary bodies, of which otherwise we never 

 could have obtained any knowledge. 



NEW FACTS AND THEORIES RESPECTING METEORS. 



Several points of interest, bearing on the question of meteors, have 

 recently been deduced from a large Catalogue of Fire Balls and 

 Aerolites, published in the British Association Reports for 1860. 



First, there appear to be indications of an eight-yearly maximum 

 and minimum period for aerolitic meteors, the calculated years of 

 maxima being 1859, 1851, 1843, 1835, etc., and very nearly agreeing 

 with observed years. Secondly, there appear to be aerolitic and me- 

 teoric epochs both distinct from and common to each other. Thirdly, 

 while the aerolitic class of meteors in its total is rather under the 

 average for August, which is the principal and most constant month 

 for an abundance of sporadic meteors, it is over the average for No- 

 vember, likewise a month noted, though not so regularly, for an abun- 

 dant display of meteors. Fourthly, as regards the observed direction 

 of aerolitic and first-class meteors, there would seem not to be any 

 very great tendency one way or the other ; it might have been more 

 natural to have expected a much more decided leaning to a westerly 

 direction. The sudden change from an easterly direction, in Sep- 

 tember and October (about the time of the autumnal equinox), to a 

 westerly direction in November, is remarkable. In January the 

 prevailing direction was S. E. ; in February, E. N. E. ; in March, 

 N. N. W. ; in April, W. ; in May, N. W. ; in June, S. ? ; in July, 

 N. W. ; in August, W.? ; in September, E. N. E. ; in October, E. S. E. ; 

 in November, W. N. W. ; and in December, S. ? Fifthly, there 

 have been far more falls of meteoric stones in the months of June 

 and July than in the months of December and January. Sixthly, 

 taking the whole year, there is a greater tendency to equality of dis- 

 tribution in the aerolitic class of meteors than the smaller shooting 

 stars and sporadic meteors ; and it is highly probable that there is a 

 distinction to be allowed between these two classes as regards orbit 

 and physical characters. The meteors for December appear of late 



32 



