Number 145 (Story #1), September 28, 1993 by Phillip F. Schewe and Ben Stein SUPERCONDUCTIVITY HAS BEEN OBSERVED ABOVE 150 K for a mercury-barium-calcium-copper oxide material squeezed to a pressure of 150 kbar, which is about 150,000 times the pressure of the atmosphere. The previous record of 133 K was observed in a similar mercury-bearing material earlier this year. The new material, known as Hg-1223, was made by C.W. Paul Chu and colleagues at the University of Houston. Why pressure should increase the superconducting transition temperature is not completely understood, but based on previous experiments Chu believes that making the appropriate chemical substitutions in the material might duplicate these high temperatures at normal pressure. (C.W. Chu et al., Nature, 23 September 1993.)