That must be an extremely high energy source they are using. Neutrons capable of this you'd not want to meet :-). They repeated the first experiment, in which they had fired pulses of neutrons from the Cern underground laboratory near Geneva through solid rock to subterranean particle detectors at the Gran Sasso National Laboratory in Italy about 750km (466 miles) away. OR the proof reader was travelling at far slower than the speed of write. Russell --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .