ocr: NATIONAL GEOGRAPHIC Geographica - Peering at an Unseen World in Almost-living Color That's not an imagined creature from outer space; it's an ordinary blackfly. This scanning clectron microscope (SEM) image, made by California-based microg- rapher David Scharf, demonstrates advances in the miniature world of scanning micros- copy. Ordinarily an SEM: passes a beamof electrons, rather than light, acrossi ject's surface to produce a. 3-D When the GEOGRAPHIC fearared schar revolutionary work inalie February 1977 issue, a note with phe black-and-white uages explained that "lectrons cupnor convey co ...
