Number 72 (Story #2), March 23, 1992 by Phillip F. Schewe and Ben Stein MAGNETOTACTIC BACTERIA , described at the March Meeting by Richard Frankel of Cal Poly, produce particles such as magnetite (Fe3O4) and greigite (Fe3S4). Protein-containing membranes in the bacteria line up between 10 and 20 of these particles, forming a permanent magnet sensitive to the Earth's magnetic field and allowing the bacteria to quickly locate oxygen regions conducive to their survival. In what Frankel called a "masterpiece of permanent magnetic engineering," the bacteria produce particles over a narrow size range centering around 500 angstroms. Frankel said that in the future, this process may be duplicated in order to produce materials such as yttrium-barium-copper-oxide particles, the raw materials for high-temperature superconductors.