Dr. Walter Flight — History of Meteorites. 155 



and fill the gap that has hitherto separated the carbonaceous from 

 other meteorites. 



If some differences are to be traced between the remarkable rocks 

 and irons of Ovifak and known meteorites, others still greater 

 present themselves, when we compare the Greenland masses with 

 terrestrial rocks, even with the basalts and diorites, near which it 

 might be proposed to class them, on account of the occurrence in 

 them of magnetite, and of the crystalline arrangement of their silicates. 

 Iron has not hitherto been found as metal inclosed in basalt, except 

 on very rare occasions (as by Andrews in the basalt of Antrim, 1 and 

 then only in fine particles, and apparently not alloyed with nickel 

 and cobalt), while troilite is a meteoric mineral, and has never been 

 met with in a terrestrial rock. 



But if the weight of evidence favours the assumption that these 

 masses are of meteoric origin, there remain the following considera- 

 tions, to which attention has been drawn by Eammelsberg, sup- 

 porting the view that they may possibly have been erupted. 



Of the rocks composing the globe, the greater portion accessible to 

 us have been modified by the action of water. There is one class of 

 which this cannot be said : the molten masses brought to the sur- 

 face by volcanos, the various rocks we term " lava." However 

 they may differ as regards constituent minerals, they have amongst 

 them a family resemblance, and it is with them that the meteoric 

 rocks may be compared. The old lavas of Iceland and Java consist 

 of augite and anorthite, as do the meteorites of Juvinas, Jonsac and 

 Stannern. The " bombs " of the prehistoric volcanos of the Eifel 

 are composed of olivine, augite, bronzite and chromite, minerals that 

 are commonly met with in meteorites. Hence arises the question : 

 Are these masses, so similar in their lithological characters to the 

 meteorites, samples perhaps of the inner unchanged nucleus of 

 our planet ? Does the original mass of the earth differ in point 

 of magnitude only from the fragments which yield to its attraction ? 



The mean density of the earth is greater than that of the minerals 

 composing the rocks of the outer crust. The volcanic rocks and the 

 meteorites, which in point of chemical constitution are basic, are 

 alike denser than this crust. The presence of metallic iron, a 

 characteristic feature of meteorites, points to the absence of water 

 and free oxygen as one of the essential conditions for their form- 

 ation. Terrestrial rocks rarely contain iron, but it is replaced by an 

 oxidized form of iron, — magnetite. Only in combination with 

 platinum is it found in the metallic state. May the rocks of the 

 interior of our globe contain this, the most important of all the 

 metals, in an uncombined condition ? 



It has been pointed out by Daubree that a region like Greenland, 

 where doleritic rocks cover so wide an area, appears in a marked 

 degree to present the conditions necessary and favourable for the 

 upheaval of masses from very considerable depths. 



Another phase of the question to which he directs attention 



1 A. E. Reuss detected the presence of iron in some Bohemian basalts by Andrews' 

 method. (Kenngott's TJebersicht Result. Min. Forschungen, 1S59, 105.) 



