Letter from Thomas Gold to Dr S I Rasool, Institute for Space Studies, Goddard Space Flight Center, NASA, New York Tells Dr Rasool that the Mercury paper looks fine to him and that he is glad that the dilemma can be resolved. Says that 'If our explanation is right the axis ought to be normal to the plane of the solar system, not the inclined orbit of Mercury, because the plane precesses fast compared with tidal relaxation'. Asks if there is any way of measuring this. 18 October 1965