VE day isn't the only big anniversary this year - 1995 also marks the centenary of the invention of the X-ray and proof that even the greatest scientists get it wrong sometimes. Lord Kelvin's contribution to learning may have been so great that they named a hall and a unit of temperature after him, but he still dismissed the first reports of the new technique as a hoax. At the same time he predicted that heavy machines would never fly, that radio would never work and was out by a factor of 100 about the age of the Earth.