EXrERIMENTS RELATIVE TO METEORITES. 327 



a thin and crystallizorl ])ellicle, while the intorior is coinj)osod of lonQ- crystals 

 of eiistatitc which traverse it : these two substances are thus i^f'rouped coiiforiiiahlv 

 to their order of fusibility. Very frequently the needles of enstatite exteiul 

 to the surface of tlie mass, with an arrangement which perfectly resembles 

 that of the mica called palmate, contained in certain ])egmatites of the Pyrenees 

 and the Limousin. This dendritic grouj)ing of the enstatite has a very decidcid 

 tendency to aiTange itself under a constant angle. There is observable, also, 

 in the two species of luagnesian silicate, a remarkable tendency to group ihem- 

 selvcs regularly one on the other, as is seen in the staurotide and the disthene ; 

 and certain crystals having the form of ])eridot serve, as it were, l)ut for the 

 union of the numerous needles of enstatite which traverse them, thus recalling- 

 the structure of certain pscudoraor])hs. 



These mixtures, easily discernible by the naked eye, pass into others which 

 are indiscernible, and in which the substance, having a homogeneous a})pearance, 

 like certain natural meteorites, betrays its compound nature only by a separation in 

 the presence of acids. It should be remarked, further, that meteorites include, 

 certain substances, such as the silicate of alumina, which form no essential part 

 of the peridot nor of the enstatite, but which remain hid in the crystiils of these 

 two mhieral species, doubtless by virtue of the affinity which M. Chevereul has 

 tQvmvdcapiUan/. * * * l'hea/u/«//?o»s »/(?fco?v7ra, of which those of Juvinas, 

 of .Jimzac, and of Stannern afford the best-known examples, give a })r()duct 

 entirely ditl'erent from all the magnesian meteorites which we have been consider- 

 ing : it is a vitreous mass, sometimes ribandcd by incipient devitrilication, but wilh- 

 out crystals of jjcridot or of enstatite. 



In the ^'ourse of these investigations the presence of a body has been recog- 

 nized which does not appear to have been observed until now in the magnesian 

 meteorites; I speak of titanium, distinguishable by its characteristic color and 

 its iinalterability on contact with acids, and which has been thus detected in the 

 melted meteorites of Montrejeau and Aumale.* 



niTTATIOX OF METEOKITKS Or THE COMMON TYPE BY KEDUCTION^ OF 



SILICATES. 



The fusion of meteorites of the common type produces, as has been scon, two 

 principal minerals, peridot and enstatite. Hence it was to the terrestrial rocks 

 characterized by the presence of these two minerals that resort was had, in the 

 first instance, for the experiments in contemplation. The first step was to fuse 

 tliem in crucibles of earth without the intervention of a reducing agent. 



By simi)le fusion in such a crucible peridot was converted into a green trans- 

 lucent mass covered with crystals of peridot and entirely crystalline in the interior, 

 as appears by its acti(Mi on polarized light. Its structure is often lamellar, like 

 that of the jjcridot of the scoriie.t The fused peridot contrasts, therefore, by its 

 cousistence with the granular and but little coherent peridot usually contained 

 in basaltic rock"s.| Lherzolite, formed of a mixtiu'e of peridot, enstatite, and 

 pyroxene, melts still more readily than peridot, and gives masses which repro- 

 duce the natural rock so as to be easily mistaken for it; with this difference, 

 that, on the surface and in the interior, needles of enstatite may be observed, 

 which wtTO not distinguishable before the fusion. Thus the needles, perfectly 



'^ This metiil. niiuuunced iu tliu pyroxniiic meteorite of Jiiviuas, by M. Rauimelsbtrg, lias 

 appeareil, also, very clearly on the <;lobules of iron obttiitietl by tin- t'nsion of that nictuDrue. 



t Tlu! peiidot on wliieli mostot the cxpeiirneuts here cited were niiide comes from the basalt 

 near Laiif^eac, (llaiUv-l^oire, ) wlieus it abounds. A jieridot of this locality, analyzed by 

 lifitliii-r, yielded \i'< jjer JOU ot protoxide of iron. 



t The basalt appears not to have had, at least iu general, a temperature sufficiently hifjh to 

 melt the lai;;;c fragments of peridot which wore i nbedded in it. Yet it may. perhaps, have 

 been capable vi dissolvinj;;' ii part, and havo thus piven rise to the crystals, woU detiued but 

 of small dimension, which are sometimes disieuiiuated llirough it. 



