Moorish Cement

1847 Scientific American  
Case Hardening Iron. The following are among the several meth ods of case hardening by means of prussiate of potash . The piece of iron, alter being polish ed , is to be made brightly red hot, and then rubbed or sprinkled (lver with the above �alt in fine powder, ll pon th e part i ntended to be bardened.
doi:10.1038/scientificamerican05291847-288d fatcat:emxwwg7idja43fzsxhxi5foyvm