After a week with student friends at Barmouth, Darwin returned home on 29 August to find a letter from Henslow proposing him as a suitable (if unfinished) gentleman naturalist for a self-funded supernumerary place on HMS Beagle with captain Robert FitzRoy, more as a companion than a mere collector. The ship was to leave in four weeks on an expedition to chart the coastline of South America.[33] Robert Darwin objected to his son's planned two-year voyage, regarding it as a waste of time, but was persuaded by his brother-in-law, Josiah Wedgwood, to agree to (and fund) his son's participation.[34] Darwin took care to remain in a private capacity to retain control over his collection: the ship's surgeon Robert McCormick expected to be the official naturalist.[35]