Reports that Japanese researchers had discovered a ceramic superconductor that worked at zero degrees Fahrenheit – minus 17`C – are not taken seriously back home, Koichi Kitazawa, a professor of industrial chemistry at the University of Tokyo told a conference at the Massachusetts Institute of Technology last week: his statement lends weight to the belief that minus 180`C or so is the practical limit for high-temperature superconductivity for some years (CI No 852).