in 1831 imlay journeyed to the illawarra district and on his return reported a disease resembling smallpox had broken out there among the aboriginal population. (although the disease was never endemic on the continent, it was the principal cause of death in aboriginal populations between 1780 and 1870.) he was on the move again in 1832 when he accompanied governor (sir) richard bourke (1777-1855) on a tour of inspection of southern new south wales.