AEROLITES. 225 



are attracted b} the magnet, and possess entirely the nature 

 of that found in larger masses. To this class belong, for ex- 

 ample, the stones of Blansko, Lissa, Aigle, Ensisheim, Chan- 

 tonnay, Klein-Wenden near Nordhausen, Erxleben, Chateau- 

 Renard, and Utrecht. The stones of the other class are free 

 from metallic admixtures, and present rather a crystalline 

 mixture of difierent mineral substances ; as, for example, the 

 stones of Juvenas, Lontalax, and Stannern. 



" Since the time that Howard, Klaproth, and Vauquelin 

 first instituted the chemical investigation of meteoric stones, 

 for a long time no regard was paid to the fact that they 

 might be mixtures of separate combinations ; but they were 

 examined only for their total constituents, and it was consid- 

 ered sufficient to draw out the iron by the magnet. After 

 Mohs had directed attention to the analogy between some 

 aerolites and certain telluric rocks, Nordenskjold endeavored 

 to prove that the aerolite of Lontalax, in Finland, consisted 

 of olivin, leucite, and magnetic iron ore ; but the beautiful 

 observations of Gustav Rose first placed it beyond doubt that 

 the stone of Juvenas consists of magnetic pyrites, augite, ai:d 

 a feldspar very much resembling labrador. Guided by thi<, 

 Berzelius endeavored, in a more extended essay [Kongl. Veten 

 skaps-Academiens Haiidlingar fur 1834), to eliminate, also 

 by chemical methods, the mineralogical nature of the sepa- 

 rate combinations in the aerolites of Blansko, Chantonnay, and 

 Alais. The road happily pointed out by him beforehand has 

 subsequently been abundantly followed. 



" a. The first and more numerous class q{ meteoric stones, 

 those with metallic iron, contain this disseminated throujrh 

 them, sometimes in larger masses, which occasionally form a 

 skeleton, and thus constitute the transition to those meteoric 

 masses of iron in which, as in the Siberian mass of Pallas, 

 the other materials disappear more considerably. On account 

 of the constant 'presence of olivin, they are rich in magnesia. 

 The olivin is that part of the meteoric stone which is decom- 

 posed when it is treated with acids. Like the telluric, it is 

 a silicate of magnesia and protoxide of iron. That part which 

 is not attacked by acids is a mixture of feldspathic and au- 

 gitic matter, whose nature admits of being determined solely 

 by calculation from its total constituents, as labrador, horn- 

 blende, augite, or ohgoclas. 



" 3. The second much rarer class of meteoric stones have 

 been less examined. They contain partly magnetic iron ore. 

 olivin, and some feldspathic and augitic matter ; some oi 



K 2 



