THE PRE-TERRESTRIAL HISTORY OF METEORITES. 



The completion of the studies for students relating to the 

 composition and structure of meteorites, which have recently- 

 been published in this Journal, furnishes an opportunity for me 

 to record certain deductions which seem to me warranted by the 

 facts there presented, but which, being largely theoretical, had 

 best be stated as the expression of individual opinion. 



That theories of the origin and cosmic history of meteorites 

 have been propounded before, and that these have varied widely 

 in character, the present writer is well aware. These theories 

 may be mentioned at the outset, together with the names of 

 those who have given them special support, without, however, 

 entering into any discussion of the merits of each. 



Meteorites have been declared to be (i) terrestrial matter 

 discharged into space by the volcanoes of the earth and returned 

 to it again (Sir Robert Ball); (2) matter discharged from 

 the volcanoes of the moon (La Place, J. Lawrence Smith); 

 (3) matter ejected from the sun (Sorby); (4) portions of 

 shattered stars (Meunier); (5) portions of a shattered planet 

 (Boisse); (6) portions of comets (Newton); (7) clouds of gas 

 or dust cemented and solidified by the action of the earth's 

 atmosphere (Brezina). 



All of these hypotheses have been urged by men of eminence, 

 each urging strong reasons for his views. These reasons can be 

 learned by study of the original authorities, and the discussion 

 of them in the present article is not a part of my purpose. I 

 shall endeavor here simply to present my own views and my 

 reasons for the same. 



The study of meteorites has shown that : 



1. The majority of iron meteorites are octahedral. 



2. The majority of stone meteorites are chondritic, and contain consider- 

 able glass. 



3. Between iron and stone meteorites there is every gradation — they are 

 formed of the same sort of matter. 



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