THE METEORS OF OCTOBER, 1877. %m 



Of the total number (522) seen, I carefully registered the apparent paths 



and other details of 429, their estimated magnitudes being as folliows : — 



J^lst, 10 ==3rd, 100 



=lst, 22 =4th, 144 



=2nd, 83 5th and below, 70 



In the early part of the month, I looked toward the northeast sky, and 

 after the 7th either towards the northeast or southeast. My observations 

 prove that meteors were unusually abundant between Oct. 1-20, and I calcu- 

 culate that during the twenty days over which they extended, no less than 

 57,600 shooting-stars brighter than or as bright as 5th magnitude stars en- 

 tered the earth's atmosphere (night and day, and both hemispheres included) 

 Large as this number appears, it will be readily conceded that it closely ap- 

 proximates the truth. I have already mentioned that the horary number 

 was 15 for the sphere of vision of one observer. Now, one pair of eyes cer- 

 tainly cannot command more than one quarter of the visible heavens, there- 

 fore we must adopt 60 as the hourly rate for the whole of the visible sky. — 

 Doubling this to include the invisible hemisphere, we have 120. per hour \ 

 multiplying this by the number of hours in a day, we get 2880 as the di- 

 urnal rate, and finally by the 20 days, through which my watches endured, 

 we have for our product 57,600. 



These, however, merely represent the number clearly visible to the eye 

 on a cloudless starlit night. The number invisible must have been vast in- 

 deed, and beyond all conception. There are probably hundreds of thous- 

 ands of these minute planetary stones falling into our atmosphere, every 

 day, and too small to be discerned with the unaided eye. It must not be 

 imagined however that the horary number of visible shooting-stars, as I 

 observed them this October, is maintained during the whole year. It is 

 excessive, for the spring months are usually less prolific than the autumnal 

 months. 



From my own observation of 2081 meteors during the last five months 

 (July-Nov.), in 149f hours and a half watching (about equally divided be- 

 tween a. m. and p. m.), the hourly number was 13.3 and from this computa- 

 tion I have excluded the Perseids (385), which is such a numerous system 

 that to include it in any calculation of the average hourly numbers percep- 

 ceptible on ordinary nights of the year would be manifestly unfair, though 

 it is equally certain that it cannot be excluded from any investigations as to 

 the annual or monthly number of visible shooting-stars. Excluding this 

 rich shower, however, for the present, and taking 13.3 as the horary rate of 

 the last five months, we may easily calculate that if this is maintained 

 during the year, we have annually more than 930,000 meteors entering our 

 atmosphere, at least equal to 5th magnitude stars. 



If we include the great Ferseid system of August, the number would be 

 much greater (in fact 1.163,330), for on August iOth last alone, 1 calculate 

 that fully 10,000 visible fragments of this single shower fell towards the 

 earth. Such facts amply prove the enormous numbers of these bodies that a©- 



