 In a letter home started on 22 May, Darwin told his father that he had decided to take Covington on as a servant – 

He had been thinking about this for some time, but had not yet consulted the captain.In an addition to the letter, dated 6 July, Darwin announced that he had FitzRoy's agreement, and an unexpected saving –
As well as working as a servant and general amanuensis, writing out Darwin's records of investigations, Covington became Darwin's assistant as a collector, hunter and taxidermist.In addition to his duties, Covington kept a personal journal regarding his impressions of the voyage.