Photomacrographof sectionof a knife, from tenth century, Bohemia. Welded together from three plates: hard steel edge, hard steel side strip, wroughtiron blade. Photomicrographsof sections.Above: Ferrite, Migration period spear-head.Below: Ferrite and dark pearlite areas, carburizedHallstatt knife. Magnifiedrespectivelyca. 145 and 140 x, etched. Radiograph of a rust-eaten Celtic chain, Moravia. Courtesyof K. Ludikovský. 238