O. C. Farrington — Analysis of "Iron Shale." 309 



The ferric chloride is, however, reduced by contact with iron 

 to form ferrous chloride again : 



4FeCl 3 + 2Fe = 6FeCl 2 



so that the process is continuous. In addition there may 

 occur a formation of free acid through hydrolysis of ferric 

 chloride : 



4FeCl 3 + 6H 2 = Fe 2 6 H 6 + 6HCl + 2FeCl 3 . 



This acid would obviously likewise exert a decomposing 

 action. 



In conclusion, it may be said that the view of Foote and 

 Barringer that the oxidation which produced the "shale" 

 took place during the fall of the meteorite, is not that of the 

 present writer. In the present writer's view the oxidation 

 occurred subsequent to the fall of the meteorite, and was so 

 gradual that the production of the shale can be explained only 

 by assuming that the fall took place many years ago. 



Field Museum, Chicago, June 15, 1906. 



