EXPERIMENTS RELATIVE TO METEORITES. 329 



results still more decided and characteristic by operating- on masses of peridot 

 and llierzolite weiij^'liing' as much as 12 kilograms. Precii)itates of iron, relatively 

 vohiminons ami susee[)til)le of being submitted to the experiment of Widman- 

 stiitteu, have thiis been obtained; also a very distinct parting and the ajipear- 

 ance of a regular iigure [iroduced by the unattached matter. 



Further, it has tims been possible to observe a fact which in operating with 

 small granules had passed unperceived, but the importance of which will not 

 escajie those who have had occasion to examine the natural external surface of 

 masses of meteoric iron. I speak of the angular forms, such as are presented by 

 the iron meteorites of Charcas and of San Francisco del Mesquital, and also of 

 those problematic capsides, such as are displayed particularly In' the first of these 

 blocks, and still more distinctly by that of Juncal, {Coiupfcs Ixcndu^, t. Ixvi, p. 

 701, 1868.) Certain of these gramdations present the angular forms, and their 

 artilicial surfaces bear, moreover, depressions here and there, characters wholly 

 analogous to those which we have just recalled. They have manifestly origin- 

 ated during' the cooling b\' a sort of motilding of the iron against the stony mat- 

 ter, which has become tough, if not solid, when the iron was still possessed of 

 fluidity. In presence of this result, we would seem to be brought back to the 

 hypothesis emuiciated on occasion of the iron meteorite of Toula, and the angular 

 f(jrms of the meteorites of Charcas and San Francisco del Jlescpiital, {Comptcs 

 licmluSj t. Ixvi, p. 573,) according- to which hypothesis the meteoric irons were 

 produced in the midst of silicated masses, between which they were moulded and 

 from which they were ultimately detached. 



"We have thus seen meteorites reproduced in the general features of their com- 

 position ; we will find that they have been imitated with eipial success in certain 

 intimate details of their structure. 



If we examine with the microscope a thin lamina of peridot or llierzolite after 

 fusion, we observe, as in the greater part of meteorites of the common tyjie, those 

 series of parallel straight lines resend)ling strokes of the burin, remarkable for 

 their regularity, in the Uiidst of clefts of irregidar form. These lines are owing 

 to the existence of planes of cleavage. Moreover, fine needles of enstatite, par- 

 allel and perceptibly ec^uidistant, arranged also in (dusters, recall the d(,'tails of 

 texture disclosed by the microscopic examination of a number of meteorites* 



The globular structure is so frequent in meteorites of the connnon t\\w. that it 

 Las earned for this wlude group the denomination of chondrite. Now, we see 

 similar grains, or spherules, make their appearance in many of the ex})enments 

 conducted by the fusion of magnesiun silicates. Among these globules some 

 have a smooth surface, others a drused sm-face, or one rough with small micro- 

 scopic crystals. The latter entirely rest^mble the globules of the meteorite of 

 Sigena, (17th November, 1773,) of the friable variety. These globules are not 

 attacked by acids, like those of the meteorites. The analysis of a sjK'cinien has 

 sh(jwn that it contains more silex than the bisilicate. Lastly, the surfaces of fric- 

 tion, with a coating of graphitic a])pearauce, which many meteorites present in 

 the interior, as, for exami)le, that of Alexandria, {2d February, 18G0,) are well 

 imitated with the fused silicates which contain iron reduced to very small grains, 

 when two fragments are rubbed one against the other. 



In another series of experiments, hydrogen, not charcoal, was employed as the 

 reducer, and the results were found to be of the same order; thus, llierzolite and 

 pyroxene exposed to a current of hydrogen abandon, in the state of metal, the 

 iron which existed in the form of silicate of protoxide. The reaction may bo 

 ellected at a temperature which does not exceed the red. Under these same? con- 

 ditions the jihosphates, whether alone or in the presence of the silicates, are 



* Apart from tlie instauco of the meteorite of Aumalo, I will refer tlio retuler to tlio.se which 

 are iif^urcd in the importiiiit woric of my learned fiiend Gustiive Rose, (or tiie met( orites of 

 Kiasnoi-I'^oi, of Stuuropol, and for the peridot of tho iron meteorite of Ptillus, (i'i. i, Fig. 

 lU, and I'l. iv, FigH. 7, «, 'J.) 



