Show A process of hardening steel by means of if an all clec electric current tra traversing the red liot hot metal lias his been invented in france experiments made with will tools thus hardened are sald said to have given III ina results A sharpened table knife elit f ait a one inch iron wire as if it had been a atrin string iron iroll bars were ensley cut with willi a circular circular ir cular saw drills pierced caststeel cast steel plates with twice the speed and e anse ie ot of ordinary drills and in ili all the experiments the tools showed no injury |