Buchan is not mentioned often in the surviving journals from the voyage. In Banks' journals, his first appearance is a note that Buchan drew views of the Cape Verde islands on 30 September 1768. Buchan's epilepsy first comes up in Banks' journal during an expedition in Tierra del Fuego. Endeavour lay at anchor in the Bay of Good Success on 15 January 1769. On 16 January, a group of eleven people including Banks, Daniel Solander, Buchan and four of Banks' servants went on an expedition in the country, attempting to reach the top of the hills. During this, Buchan had an epileptic seizure, a fire was lit, and the servants stayed with Buchan while Banks and others went on to search for alpine plants. On their return, the weather became cold and it started to snow, making it impossible to return to the ship. Two of Banks' servants, Richmond and Dorlton, got drunk on whiskey and died from exposure that night, but Buchan recovered.
