Dr. Walter Flight — History of Meteorites. 161 



their satellites, the comets, the shooting-stars, the meteorites (" qui, 

 pour moi, sont de petites planetes"), and the zodiacal light, a disk of 

 asteroids or cosmical matter massed together near the sun, he gives 

 expression to the following views respecting the polar aurorse : Not 

 only solid masses, large and small, but clouds of " uncondensed " 

 matter probably enter our atmosphere (probabile etiam est nebulas 

 materiei primigenise sine nucleo condensato in atmosphaeram venire). 

 If, from our knowledge of the chemical composition of the stones and 

 irons which fall to the earth's surface, we may draw any conclusion 

 respecting the chemical constitution of these clouds of matter, it 

 appears possible that, as many of these stones consist partly, and 

 the irons almost entirely, of iron and nickel, the attenuated cloud- 

 like matter may also contain a considerable proportion of these mag- 

 netic metals. 



Let such a cloud, the greater part of the constituents of which have 

 magnetic characters, approach our earth, which we have been taught 

 to regard as a great magnet. It will evidently be attracted towards 

 the poles of this magnet, and, penetrating our atmosphere, the parti- 

 cles which have not been oxidized and are in a state of extremely 

 fine division will, by their oxidation, generate light and heat, the 

 result being the phenomenon which we term a polar aurora. Obser- 

 vations have shown that the seat of these phenomena is about, not 

 the geographical, but the magnetic poles. Not a few facts, even at 

 that time, could be advanced in support of the theory, which assumes 

 the occasional presence of metallic particles in the higher regions 

 of our atmosphere. More than once such particles had been dis- 

 covered in a fall of hail. Eversmann 1 found in the hailstones which 

 fell on the 11th June, 1825, at Sterlitamak, 200 wersts from Oren- 

 burg, Siberia, crystals of a compound of iron and sulphur, in which 

 Hermann found 90 per cent, of that metal. 2 In hail which fell in 

 the province of Majo in Spain on the 21st June, 1821, Pictet 3 found 

 metallic nuclei which were proved to be iron ; and the hail which fell 

 in Padua on the 26th August, 1834:, was observed to contain nuclei 

 of an ashy grey colour. The larger ones were shown by Cozari 4 to 

 be attracted by the magnet, and to contain iron and nickel. " It would," 

 wrote Baumhauer, " be very interesting, in verification of this 

 theory of the origin of polar auroras, to detect in the soil of polar 

 areas the presence of nickel." This theory, which at the time it was 

 promulgated appeared so rash that it met with severe criticism by 

 the great Berzelius, 5 has gained support from recent researches ; 

 among others, the discovery by Heis of the simultaneity of boreal 



1 E. Von Eversmann. Archivfiir die gesammte Naturlehre, iv. 196.— A. Neljubin. 

 Archiv fur die gesammte Naturlehre, x. 378. — Hermann, Gilbert's Ann., lxxvi. 340. 



2 Though von Baumhauer cites this instance, it does not appear that the metallic cha- 

 racter of the "crystals" was fully established in this case Neljubin found them to 

 consist of 70 per cent, iron oxide, and 17*5 per cent, of other metallic oxides. In 

 fact, this substance appears to have been an impure limonite, like that which fell at 

 Iwan, in Hungary, on the 10th of August, 1841, and was probably not meteoric. 



3 Pictet. Gilbert's Ann., lxxii. 436. 



4 D. L. Cozari. Ann. Sc. Regn. Zomb., 1834, Nov. e Dec. New Ed. Phil. Jour., 

 xxx vii. 83. 



5 Jahresbericht, xxvi. (1847), 386. 



DECADE II. — VOL. II. NO. IV. 11 



