ABSTRACT
In 1796, Nevil Maskelyne, the fifth Astronomer Royal of Great Britain, sacked his experienced assistant David Kinnebrook because Kinnebrook’s measurements of the precise moments when stars crossed fixed reference points were consistently slower than his own. Maskelyne is now remembered for his attempts to suppress and undermine the achievement of John Harrison whose innovative clocks were the first practical solution to the problem of determining longitude: a problem that Maskelyne also had a strong vested interest in solving.1 This discreditable episode suggests that Maskelyne was obstinate and self-centred, but he was also a capable observer and a dedicated scientist and, through the Royal Society, in touch with the wider science of his time. His harsh treatment of Kinnebrook could be justified in terms of the little then known about human minds. It was not then understood that there might be individual differences in decision speed that even diligent practice, effort and attention cannot alter. The story of how we came to discover why these ideas are mistaken neatly illustrates that science progresses, not only through abrupt brilliant insights but far more often, by a gradual realisation that widely accepted ideas must be wrong.
