He was not an outstanding artist, but his paintings and sketches have great charm and spirit and have considerably enriched natural history art. He remained at Cape Town to the end of 1837, then for the next three years he resumed his work in Western India as field engineer to the Sindh Force. From 1841 to 1843, Harris led a British diplomatic mission from Bombay to Sahle Selassie, Negus of Shewa, at the time an autonomous district of Ethiopia, with whom they negotiated a commercial treaty. They also collected extensive scientific data during the trip. Harris was gazetted major in 1843 and was knighted in England the following year for his services. After being knighted, Harris acted as executive engineer at Dharwar Dion and Poona. He died near Poona as a result of fever, aged 41. Harris married Margaret Sligo, daughter of George Sligo of Auldhame in Scotland and niece of General Sir James Outram. Their marriage was childless.