>No mention in the article of the wires used in the Russian unit, >but says Seebeck himself used bismuth and copper The effect works best in certain semiconductor junctions. I once had a book about $SUBJ that described the Russian items in detail. I do not remember what they used. Some Telluride or something like that. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.