452 M. Haidingev on the Original Formation of Aerolites. 



" Callum's drops or globules." Professor T. H. Newton of Yale 

 College, New Haven, Conn. U.S., says (New York Tribune, Au- 

 gust 22, 1860), " it is calculated from perfectly reliable observa- 

 tion, that not less than 10 millions of meteors enter the atmo- 

 sphere every day, and are burnt up*." 



This would then be 3650 millions per annum, which would 

 again materially increase the total amount of meteoric matter 

 contained within the above-mentioned space. But is there not 

 some probability that beyond our own system of fixed stars, all 

 space is replete with such bodies, of which only a proportional 

 minimum, and that transitorily, make up part of our own solar 

 system ? Not that all of them may be burned away or melted ; 

 for the large 4 lb. stone of Segowlee, described by me, has its 

 edges quite sharp and nearly unaltered, some of them being 

 rounded only to a depth of not quite one-twelfth of an inch. 

 Meteorites composed of less dense matter, while moving rapidly, 

 may be frequently again repelled into space by the resistance of 

 compressed air. For this reason meteorites of earthy or carbo- 

 naceous like consistence, as those of Bokkeveld, Alais, &c, are 

 of particular importance, a3 well as rare. Meteorites are far 

 behind our terrestrial rocks with regard to diversity of mineralo- 

 gical character. The minerals composing granite, gneiss, mica- 

 schist, and others, representing the most solid basis of the terres- 

 trial crust, are wanting in them ; and, to name a particularly 

 important species, they are totally destitute of pure silica or 

 quartz f. 



* If, as I presume he does, Prof. Newton means that this represents the 

 total number of meteors which enter our atmosphere daily, and that all 

 these are, as a matter of course, consumed in it, I think he is mistaken, 

 the number of meteors so consumed being in all probability limited to such 

 only as burst or become dissipated in sparks. These form but a small por- 

 tion of those that apparently fly almost instantaneously through the upper 

 strata of the air (at an average height of 65 miles, as recently proved by 

 Prcf. Secchi at Rome), and pass off again, perhaps tangentiallv, into inter- 

 planetary space. Prof. Vaughan of Cincinnati, U.S., thinks it probable 

 that the solid nucleus of an ordinary shooting-star is no bigger than a hail- 

 stone; and this is only analogous to what takes place with large aerolitic 

 meteors. There are cases of large and well-observed meteors, which after 

 bursting, sometimes even with noise, into two or more parts at a height 

 of 40 miles or so, have undoubtedly again passed into planetary space, 

 — another proof also that the smaller shooting-stars may do the same. 



It must not be forgotten in these rather speculative calculations, that the 

 same groups of meteors may frequently repeat themselves, that is, return 

 periodically without visible or material loss, and that, in fact, by far the 

 greater number of meteors seen are doubtless those that are periodical 

 and consequently belong to our own system. Unless it can be otherwise 

 proved, it would seem premature to suppose otherwise than that by far the 

 larger portion of meteors and meteorites of all kinds belong to the solar 

 system, and not to stellar space.— R. P. G. 



t Since these lines were written, my highly respected friend Prof. G. 



