Letter, from G[erhard] F[riedrich] Muller to Cromwell Mortimer, dated at St Petersburg That Catherine the Great wished for an expedition to Kamtshatka to compile a history and geography of Siberia; Dr Amman did not receive invitation in time; Mr Gremlin and Mr de l'Isle de la Croyere are going; that 'Le specimen literaturae Tanguticae' should be printed in London 30 June 1733