EXPERIMENTS RELATIVE TO METEORITES. 333 



phoSpluiret of iron and of nickel, hist recognized by Ik'rzelius, is found alincst 

 always associated with the meteoric iron. This, like native iron, is entin^ly 

 deficient in our rocks, where it is replaced l)y the phosphates i)articulaily I're- 

 qnent in the basic silicated rocks.* 



Without insistini^ furtlicr on some other contrasts of the same nature, we recog- 

 nize that the essential diirenuice between these meteorites ami the analo2;ous ter- 

 restrial rocks consists in this : that the first contain, in a reduced state, certain 

 substances which the second contain in an oxydized state. Everything" leads 

 tt) the belief that masses between which t«i)ere exists such a similarity of compo- 

 sititm would have been identical, notwithstanding their immense separation^ if 

 they had not undergone dilFcrent actions. 



rMPORTANCE OF TKE MAGXESIAN ROCKS OF THE rERIDOT TYPE, AS WELL 

 IN THE TElHiESTllIAL GLOBE AS IN OUR PLANETARY SYSTEM. 



Among the basic silicates there is one which presents itself with remarkable 

 constancy in almost all the varieties of meteorites, from those of iron to those of 

 Btone, properly so called ; this is peridot. In the latter it is rarely solitary (Chas- 

 signy) ; connnonly it is mixed with more acid silicates, often in undiscernible 

 parts, t On the other hand, peridot necessarily exists in the profound depths of 

 our globe. 



In etl'ect, the basalts of the most distant regions have brought up fragments 

 of it, which often remain angular, and which would l>e])ronounced to have heen 

 torn from a deep and pre-existent mass. Detached peridotic masses abound, as 

 is well known, in different volcanic regions of France, (Langeac, Haute-Loire, 

 ]\[onrerrier, Ilerault,) on the banks of the Ilhine (environs of Lake Laach,) and 

 in other countries. At the same time there are other pyroxenic rocks in which 

 peridot is abundant, as, for example, in the dolerites of the environs of JMontar- 

 ville and of ^Montreal, in Canada, wherein, according to M. Stei'ry limit, [Geology 

 of Ctoufda, ])p. 4G4, 706,) it forms sometimes nearly half of the total weight, 

 liocks rich in peridot have also been met with, traversing tlu; chalk, in the neigh- 

 borhood of Teschen, in Bohemia, and have been described by M. Tschermak, 

 who has recently published a notice on the presence of olivine in rocks, [Bul- 

 letin cle V Academic de Viennc, 11th July, 18G7). Again, peridot constitutes the 

 base of the Iherzolite which has made an eruption at man}- points of the Pyrenees, 

 among others, near the lake of Lherz, and which occurs in other countries. 

 Thus it is known in the Tyrol, and but a few years ago was discovered in New 

 Zealand, where it forms an entire chain, by j\I. de liochstetter, who has given it 

 the name of d unite ; more recently still it has been found in Nassau, at Trigen- 

 Btein, by M. I'\ Sandberger, who calls it by the name of olivinfcls, [Lconliard's 

 JaJirburh, 18G5 and 1SG7.) To this it may be added that ^l. Kjerulf has lately 

 ascertained that a rock which abounds in the environs of B(;rgen, Norway, and 

 which M. Keilliau had heretofore considered as a metamorphic grit, is composed 

 in part of nickeliferous j)eridot, with which are associated chroinated iron, and 

 talc. It may be further noticed that, after having recognized peridot in the rock 

 of Ijlfdalen, in Sweden, M. G. Hose has found it also in the augite rocks of 

 Neunjde, in Silesia. 



We. are thus led to recognize that the part fulfilled by peridot, so restricted 



* The stone of Juvinas, in which M. Rammelsberg has announced iron in the state of a 

 phosphate, only affords confirmation of this rulo ; for it contains metallic iron only in the 

 minutest quantity. It was difficult, tlieroforc, that any phospiniret of that metal should be 

 formed. 



t Of more than 150 meteoric falls represented in the collections, we possess as yet only 

 four which pertain to the aluminous type, being those of Juvinas, .Joiizac, Stanuern, and 

 Petersburg, (United States.) Tiio others are magnesian meteorites, wliich, almost all, contain 

 peridot. 



