Number 43 (Story #3), August 1, 1991 by Phillip F. Schewe and Ben Stein STM IMAGES OF NON-CONDUCTING SURFACES , such as biological specimens, may be possible with a method in which ions, rather than tunneling electrons, flow between the STM tip and a sample covered with a thin film of water serving as the ion conductor. Jian-Yang Yuan of McGill University and Zhifeng Shao and Chao Gao of the University of Virginia believe that this approach may be preferable to previous scanned probe microscope imaging techniques for non-conducting materials since it exerts a minimal force on the specimen (unlike atomic force microscopy) and does not (as in ordinary STM) employ tunneling electrons, which would necessitate the use of a very thin sample. (Upcoming article in Physical Review Letters.)