PROTON TRANSISTOR MEMORY. Electrons do most of the work in electronic devices; indeed heavier, mobile, positively-charged ions are usually a nuisance. A Sandia experiment, however, has made hydrogen ions (protons buried inside a semiconductor sandwich) into the primary carriers of information in a Si/SiO₂/Si device. Judged as a storage device, this transistor did pretty well: it retained its state (on or off) for up to 25 hours, it successfully underwent 10,000 write-erase cycles, and could be switched on a 50-msec timescale. Its chief virtue may prove to be its ease of construction. (K. Vanheusden et al., Nature, 10 April 1997.)