Abstract
James Hutton is known to have regarded exploration as an important source of geological knowledge, and to have studied the accounts of travellers with close attention. Unpublished letters in the Fitzwilliam Museum, Cambridge, however, show that he was more actively involved in exploration than had been previously supposed. During the preparation for Cook's second voyage, he gave advice about both geological and marine research. He advised Banks against making a major voyage to Arctic regions, on the grounds that it would be unprofitable geologically. He encouraged Banks and other friends to measure sea and air temperatures on their voyages, and there are indications that he himself took part in marine experiments. His interest in oceanography, which has not been discussed before, is found to complement his work in meteorology