Applied Science: Sniffing Out the Enemy

They all laughed when the U.S. Army introduced the "E63 Manpack Personnel Detector" for experimental use in Viet Nam. The device, a 24-lb. chemical and electronic version of a nose, was designed literally to smell the body odor of concealed enemy troops. Now the G.I.s—and presumably the Viet Cong, too—are more impressed than amused. The "People Sniffer," as it is known in the field, has demonstrated that it can locate hidden enemy forces and has been ordered for dozens of U.S. infantry and artillery units.

Developed by General Electric and the Army's Limited...