[a. HARVEY] THE DISTRIBUTION OF AEROLITES IN SPACE 93 



empty void in which seven or eight planets pursue their solitary circlings, 

 but a plenum, with numberless streams of matter circulating through 

 it, each composed of countless bodies of all sizes. It takes the earth close 

 upon two months to go through that part of its orbit crossed by the dis- 

 integrated particles of comet 1862 III. 



These paragraphs lead to the proper consideration of the px-esent 

 inquiry — whether there is a periodicity among aeroUtes, and whether 

 aerolites are connected with shooting stars and recognized comets. Many 

 writers assume that bolides, aerolites and shooting stars are identical. 

 The writer has come to believe that aerolites are not all the discards of 

 comets, but rather small comets themselves. To arrive at a conclusion 

 on this point, 357 have been classified according to the days they fell, and 

 it would be diiïicult to distribute the supply more evenly throughout 

 the months or the days of the year. January comes a little short, while 

 May is unusually well supplied, but there seems no special reason for 

 attaching weight to the differences, which are doubtless accidental. The 

 whole list is appended, but the summary by months is sufficient to prove 

 this statement : 



January. 24 May 42 September 31 



February 28 June 31 October 28 



March 28 July 26 November 29 



April 29 August 29 December 32 



Total 357 



The next classification made refers to the hours of their fall. This 

 important detail is not given in half the cases, but we find for these 



Between 6 a.m. and 6 p. m 127 



" 6 p.m. and 6 a. m 37 



164 

 The reason for the difference is worth inquiring into, and it is to be hoped 

 that the importance of the subject to the study of physical astronomy 

 will cause more careful records to be kept of all nocturnal bolides as well 

 as of diurnal aerolites. 



It is evident that as a general rule aerolites which strike us in the 

 day time are on their way from the sun — these which fall at night on 

 their way to it. If they were flying directly to or from it, they would be 

 most numerous at about noon or at about midnight, for at other hours, 

 equal areas on the earth's surface are obliquely inclined to the sun and 

 present a smaller target to such missiles. But they are affected by the 

 attraction of the earth, and their paths become bent, generally so as to 

 follow the earth in its course. Their velocity, we must remember, is 

 enormous. A recent committee of the British Association reports that 



