POETIONS OF THE COSMOS. AEROLITES, 



hypothesis that these hours of the night, or rather of the 

 early morning, are peculiarly favourable to the " ignition," 

 or luminousness, of falling stars ; those which shoot in the 

 hours before midnight remaining more often invisible. We 

 must long continue to persevere in collecting observations. 

 The principal characteristics of the solid masses which fall 

 from the atmosphere, both as respects their chemical rela- 

 tions, and their granular texture which has been examined 

 more particularly by Gustav Hose, have been treated by me 

 in my first volume (Kosmos, Bd. i. S. 133 137 ; English 

 edit. p. 119 122) with I believe tolerable completeness, 

 according to the state of our knowledge at that time (1845). 

 The successive labours of Howard, Klaproth, Thenard, 

 Vauquelin, Proust, Berzelius, Stromeyer, Laugier, Dufres- 

 noy, Gustav and Heinrich Rose, Boussingault, Eammels- 

 berg, and Shepard, have supplied a rich harvest (7 5 ) ; but 

 it may not be inappropriate to remember, that probably two- 

 thirds of the meteoric stones which have fallen are hidden 

 from us in the depths of the sea. Although aerolites from 

 all zones, and from the most widely dispersed places, in 

 Greenland, Mexico, and South America, Europe, Siberia, 

 and Hindostan, exhibit an obvious physiognomic simi- 

 larity, when examined more closely they are also found 

 to present great diversities. Some contain 96 per cent, of 

 iron, others (Siena) scarcely 2 per cent. Almost all have a 

 thin, black, shining, and at the same time somewhat veined, 

 crust or coating; but in one (that of Chantonnay), this crust 

 was entirely wanting. The specific weight of some meteoric 

 stones is as great as 4*28, while in the carbonaceous stone 

 of Alais, consisting of friable lamellae, it was found to be 

 only 1*94. Some (Juvenas) have a texture resembling that 



