Delhi Iron Pillar: New Insights

amorphous amount analysis ancient Indian appears Balasubramaniam bell body bottom buried called capital century Chandra Chandragupta II Vikramaditya chapter circular coins composition construction contained corrosion corrosion resistance cross section currently decorative Delhi iron pillar detailed Dhar diameter discussed earlier equilibrium evidence forge welded formation furnace further garuda Ghosh gold coins ground Gupta hammering handling height horizontal identified important indicates inscription insert iron lumps king known later layer lead legend manufacturing meaning mentioned metal method nature noted noticed observed obtained operation original oxides oxygen period phase phosphate phosphorous piece pillar iron placed polished portion possible present produced proposed protective reason region relatively river rods rough rust sample Samudragupta seen showing side similar Skandagupta slag steel stone structure surface temperature temple Udayagiri Vishnu