198 The November Shooting Stars. 



another it is not seen (as last year, for instance, in America), 

 points to a limit of breadth. But this is not the case. If we 

 consider Figs. 1 and 2 we shall see that America was on the 

 sheltered side of the earth during the whole time of the 

 display. When America had come to the side turned towards 

 the radiant, the earth's globe had, in all probability, passed 

 through the meteor-stream. So that the limits of the thick- 

 ness, and not of the breadth of the stream, were indicated by 

 the non-visibility of the meteors in America. Before the 

 display had begun in England, the meteors, were seen from 

 Kishnagur, fifty miles north of Calcutta, and they continued 

 visible until the time of sunrise there. This would assign a 

 breadth of not less than 4,000 miles to the stream. But as y 

 throughout the continuance of the display, the earth was 

 crossing the breadth of the stream at the rate of about 1,000 

 miles an hour, we can assert positively that the breadth of the 

 stream exceeded 6,000 miles. In reality, however, a very 

 much greater breadth may be assigned, with great probability, 

 to the meteor- stream. For if we consider the nature of the 

 stream and the manner in which it has been probably gene- 

 rated in the track of Comet I., 1866, we shall see the great 

 probability that its breadth exceeds its thickness. For the 

 causes tending to make meteors leave the mean plane of mo- 

 tion, are much less efficient than those tending to distribute 

 the meteors over that plane. Now the earth, during the time 

 of the display, was crossing the thichiess of the meteor-stream 

 at the rate of about 18,000 miles an hour. Therefore, since 

 the display lasted at least six hours (counting from the time of 

 its being observed in India, when England was, as yet, on the 

 earth's sheltered side), we cannot assign to the stream a less 

 thickness than 100,000 miles. The breadth is probably at least 

 ten times as great. 



It may be assumed as certain, that it is the passage of the 

 earth through the thichiess of the meteor-stream which limits 

 the duration of the display. 



I shall conclude by quoting two observations, showing that 

 the fine powder in which meteors reach the earth may be 

 detected. Dr. Rcichenbach collected dust from the top of a 

 high mountain, which had never been touched by spade or pick- 

 axe; and on analysis he found this dust to consist of almost 

 identically the same elements as those of which meteoric-stones 

 are composed — nickel, cobalt, iron, and phosphorus. Again, 

 Dr. Phipson notes, that "when a glass, covered with pure 

 glycerine, is exposed to a strong wind, late in November, it 

 receives a certain number of hho-k angular particles," which 

 "can be dissolved in strong hydrochloric acid, and produce 

 yellow chloride of iron upon the glass-plate." I quote these 



