316 EXPERIMENTS RELATIVE TO METEORITES. 



witli tlie result of experiments on wliieli I entered some time ago, by the facility 

 with which these stones disappear in consequence of their oxidation under the 

 action of water and the disintegration which is its consequence. 



CHAPTER II. 



COK"STITUTI0N OF METEORITES. — § 1. TYPES TO BE DISTI^fGUISHED. 



If we examine meteorites as regards their constitution, it will be seen that 

 some are formed of iron, evidently pure, while others consist of masses exclu- 

 liively lapideous. Between these extreme types, specimens are found of a mixed 

 flature, forming, as it were, a bond of union. Hence, it is convenient to adopt a 

 single name; applicable to all the substances which reach ns from the skies, to 

 the iron as well as stone, and even to the pulverulent or gaseous substances 

 which may have the same origin. Such a name is that of meteorite; while the 

 name of aerolite should be rejected as designating exclusively stony substances. 



We proceed to give a rapid review of the classification recentl}' adojjted for 

 the collection of the museum. [Comptes liendus de VAcademie des Sciences, t. 

 Ixv, p. 60, 1867.) 



METEORITES OF THE FIRST GROUP, OR HOLOSIDEROUS. 



Meteoric iron forms masses destitute of stony matter, and sometimes sufficiently 

 pure to be susceptible of being immediately forged; it has even been employed 

 in the fabrication of arms and utensils. No terrestrial mineral can, in this respect, 

 be compared to it; native iron, it is true, has been found on the surface of the 

 globe, but always under exceptional circumstances, when it appeared to proceed 

 from reductions accidentally effected, either by combustible gases generated in 

 volcanoes, or by the conflagration of coal-beds. This terrestrial iron, moreover, 

 never presents the characters of meteoric iron. 



This latter is characterized at once by its chemical composition, and by its 

 structure. It is always associated with different metals, among which nickel is 

 ihe most constant. It frequently contains a sulphate of iron (troilite,) isolated 

 mider a kidney-shai)ed form, sometimes cylindroidal and engaged in graphite. 

 We find, besides, a phosphate of iron and of nickel, containing magnesium, the 

 existence of which has been demonstrated by Berzelius, and to which the name 

 of schreibcrsite has been applied. Terrestrial iron has never this com})osition. 



We will cite, as an example, the iron meteorite of Caille {Alpes Maritimes), 

 the first analysis of which we owe to the Duke de Luynes, {Anncdes des Mines, 

 4th series, t. v, p. 161,. 1844). He found it to be exclusively formed of iron and 

 nickel, Avith imponderable traces of manganese and copper. The proportion of 

 nickel rises, according to this analysis, to 17.37 per 100. The results at which 

 M. Ilivot has sul)seqiventlv arrived in regard to other specimens of the same mass 

 are sensibly different, this chemist having detected neither manganese nor coppei', 

 but having found cobalt and chrome. Such divergencies teach us how much the 

 composition of these masses may vary, even in pieces with an identical aspect.* 



* Annates des Mines, 5th serie.s, t. vi, p. 554, i854. The following are the numbers he 

 obtained : 



Iron 9-2.7 



Nickel 1 ,').(; 



Chrome, cobalt, traces of silicium O.S) 



Total 9M.2 



The author thinks that the silicium is contained in the mass in the state of a siliciuret. 



