Test Tricks

After nearly 18 months of negotiations at Geneva, the U.S.-British-Soviet delegations seemed close to a nuclear test-ban agreement: an unequivocal pledge to outlaw easily detectable above-ground or underwater explosions and a voluntary moratorium on underground tests--provided the Russians join in an earnest effort to perfect devices for detecting small underground bombs (TIME, April 11). Last week, the nation's top scientific authorities on nuclear detection were called before two subcommittees of the Joint Congressional Committee on Atomic Energy, unanimously made it plain that the black art of concealing small nuclear explosions was fast outstripping the infant science of detection.

Smilingly describing himself as a "conservative" in such matters, black-browed Physicist Edward Teller, father of the H-bomb and director of the Lawrence Radiation Laboratory at Livermore, Calif., warned against the risks of submitting to a ban on underground explosions. "Very few things in science are impossible," said he. "but I do not believe that there is any great likelihood that even in four or five years from now there will be a really foolproof method of checking underground explosions down to, let us say, one kiloton [1,000 tons of TNT]. No matter how we proceed we cannot eliminate nuclear explosions of the tactical weapons size and perhaps not even some which can. serve as useful models for bigger explosions."

Physicist Albert Latter, one of the U.S. scientific delegates to the Geneva conference, explained how a 300-kiloton explosion could be so placed in a big hole that it would give off a seismographic reading of only one kiloton.

Cornell's Hans Bethe. a former presidential adviser on disarmament and longtime crusader for the test-ban agreement, set out to describe the kind of detection network that would adequately police a ban on underground explosions. In describing a system that would require 600 seismograph stations spread across the U.S.S.R. alone, Bethe only convinced his congressional listeners that the feat of detection was just as impossible as Teller said it was.

Against evident possibilities for Russian evasion of an underground test ban, Nuclear Chemist Harold Urey pointed out that Russia already has an all but infallible detection system in the U.S.: the energetic reporters of a free press. Urey hopefully predicted that there soon may be other means of detection available to those who would enforce a test ban. But last week, as testimony piled up, the argument that the probability of detection would deter the Russians from violating a test-ban treaty seemed increasingly fanciful. And the Joint Committee seemed less likely than ever to look with favor on a treaty that--in so far as underground tests were concerned--would derive its principal strength from nothing more than the good faith of the parties who sign it.

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