The Amateur Scientist; March 2000; Scientific American Magazine; by Carlson; 2 Page(s)

In January of last year I described a delightful device for detecting microfluctuations in the earth's magnetic field. The instrument was a sensitive torsion balance consisting of two small rare-earth magnets affixed to a taut nylon fiber with a tiny mirror attached to the fiber to reflect a laser beam onto a distant wall. When the instrument was properly nulled with additional magnets to cancel the earth's average magnetic field, an infinitesimal change in the earth's field rotated the rare-earth magnets and deflected the laser beam.

Originally developed by Roger Baker of Austin, Tex., this homemade magnetometer created quite a stir in the amateur community. But the device required constant visual monitoring to collect data, so it wasn't really suitable for serious science. Baker, however, suggested how someone could convert his unit into a research-grade instrument. This month I'm delighted to report that Joseph A. Diverdi, a chemist in Fort Collins, Colo., has met that challenge brilliantly.