12 H. HENSOLDT ON FLUID CAVITIES IN METEORITES. 



combinations under which these elements present themselves are, 

 with but few exceptions, those with which we are familiar among 

 terrestrial rocks. Chief among the materials which are the most 

 frequent components of meteorites is iron in its pure metallic state. 

 Indeed, by far the greatest number of the meteorites in our 

 museums and private collections are masses of iron, and in the 

 majority of the remainder metallic iron is present in greater or less 

 quantity. 



It was therefore customary at first to divide meteorites into two 

 sections — into the meteoric stones and the meteoric iron — until 

 recently, after more elaborate investigation, a more complicated 

 classification has been resorted to, and M. Daubree, divides the 

 meteorites into Holosiderites, or such as consist almost entirely of 

 metallic iron ; Syssiderites, in which a network of metallic iron 

 encloses a number of granular masses of stony materials ; Spora- 

 closiderites, consisting of stony materials through which particles of 

 metallic iron are dispersed ; and fourthly, Asiderites, or such 

 as contain no metallic iron, but consist entirely of stony material. 



Now, besides the presence of liquefied carbonic acid, which I may 

 safely say has been established in the meteorite of Braunfels, there 

 is a series of other evidences which the limit of this paper does 

 not permit me to dwell upon as fully as I should wish, bearing 

 strong proofs that this and perhaps most meteorites are not only 

 derived from mightier masses, but that they come from the interiors 

 of those masses, and are the resultants of explosions. 



If we examine those minerals which most frequently occur in 

 meteorites, we are startled to observe that they are, almost without 

 exception, those which constitute the basic lavas, those volcanic 

 productions which, as I have already pointed out, are derived from 

 the deepest-seated igneous reservoirs in the crust of our planet. 



Olivine, Enstatite, Augite, Anorthite, Magnetite, and Chromite, 

 are most frequently contained in meteorites, and they are the 

 minerals of which the so-called basic and ultra-basic lavas almost 

 exclusively consist. Masses bearing the most striking resemblance 

 to meteorites, and being composed of substances identical with 

 those which constitute the latter, are sometimes ejected from 

 volcanic vents in the shape of so-called volcanic bombs, and even 

 metallic iron, which never was believed to occur in terrestrial rocks, 

 has now been discovered in basaltic stones, alloyed even with those 

 two other metals, Nickel and Cobalt, which form so characteristic a 

 feature in the iron of meteoric origin. 



