Three commissions abroad followed, and in each case he felt unappreciated and was "invalided home", which in Naval terms implied personal dissatisfaction or disagreements.

McCormick expected this position meant the usual duties as a naturalist, as did Jameson who wrote to him in November giving detailed advice on how to make the most of the "numberless opportunities" this "exploratory expedition" would provide "for the advancement of natural history".

McCormick fully expected to put together a sizeable natural history collection with significant social value, gaining him fame as an exploring naturalist.

[3] While the preparations of the Beagle progressed in late October, McCormick met Charles Darwin who had been given an unofficial place on board as a self-funded gentleman naturalist who would be a companion to Captain FitzRoy.

Darwin wrote telling his university tutor John Stevens Henslow about McCormick: "My friend the Doctor is an ass, but we jog on very amicably: at present he is in great tribulation, whether his cabin shall be painted French Grey or a dead white— I hear little excepting this subject from him".

[1] On the latter voyage most of the naturalist's duties were performed by Joseph Dalton Hooker, with McCormick concentrating on geology and bird collecting, assisted by Thomas Abernethy.