METEORITES, METEORS, AND SHOOTING-STARS. 737 



5. A cloudy train is sometimes left along the track, both of the 

 stone-meteor and of the shooting-star. 



6. They have like varieties of colors, though in the small meteors 

 they are naturally less intense and are not so variously combined as in 

 the large ones. 



In short, if bodies that produce the various kinds of fire-balls had 

 just the differences in size and material which we find in meteorites, 

 all the difference in appearances would be explained, while, on the 

 other hand, a part of the likenesses that characterize the flights points 

 to something common in the astronomical relations of the bodies that 

 produce them. This likeness of the several grades of luminous me- 

 teors has not been admitted by all scientific men. Especially was it 

 not accepted by your late president, Professor J. Lawrence Smith, who 

 by his studies added so much to our knowledge of the meteorites. 

 The only objection, however, so far as I know, that has been urged 

 against the relationship of the meteorites and the star-shower meteors, 

 and the only objection which I have been able to conceive of that has 

 apparent force, is the fact that no meteorites have been secured that 

 are known to have come from the star-showers. This objection is 

 plausible, and has been urged both by mineralogists and astronomers 

 as a perfect reply to the argument for a common nature to all the me- 

 teors. But what is its real strength ? There have been in the last 

 one hundred years five or six star-showers of considerable intensity. 

 The objection assumes that, if the bodies then seen were like other 

 meteors, we should have reason to expect that among so many hundreds 

 of millions of individual flights a large number of stones would have 

 come to the ground and have been picked up. 



Let us see how many such stones we ought to expect. A reason- 

 able estimate of the total number of meteors in all of these five or six 

 showers combined makes it about equal to the number of ordinary 

 meteors which come into the air in six or eight months. Inasmuch as 

 we can only guess at the numbers seen in some of the showers, let us 

 suppose that the total number for all the star-showers was equal to 

 one year's supply of ordinary meteors. Now, the average annual num- 

 ber of stone-meteors of known date from which we have secured speci- 

 mens has during this hundred years been about two and a half. 



Let us assume, then, that the luminous meteors are all of like origin 

 and astronomical nature ; and further assume that the proportion of 

 large ones, and of those fitted to come entirely through the air without 

 destruction, is the same among the star-shower meteors as among the 

 other meteors. With these two assumptions, a hundred years of expe- 

 rience would then lead us to expect two or perhaps three stone-falls 

 from which we secure specimens during all the half-dozen star-showers 

 put together. To ask for more than two or three is to demand of star- 

 shower meteors more than other meteors give us. The failure to get 

 these two or three may have resulted from chance, or from some pecul- 



TOL. XXIX. 47 



