Captain John Blankett, R.N., also suggested independently to his superiors in August 1786 that convicts be used to establish a British settlement on Tristan. In consequence, the Admiralty received orders from the government in October 1789 to examine the island as part of a general survey of the South Atlantic and the coasts of southern Africa. That did not happen, but an investigation of Tristan, Amsterdam and St. Paul was undertaken in December 1792 and January 1793 by George Macartney, Britain's first ambassador to China. During his voyage to China, he established that none of the islands were suitable for settlement.