Hadfield.-8. 



Magnification lOO. 

 Etched with 5% Picric Acid in Alcohol 



Ahignihcation lou. 



I'^tchcd with 5",, Nitric Acid in Alcohol. 



Figures and 10. 



PhotomicroRrai)hs showinR that the Structure of a Gun Tube Steel is 



indei)endent of the etching: reag-ent. 



