Robert E Johnson served as a lieutenant during the United States Exploring Expedition, 1838-1842 (Senior commander Charles Wilkes). Sailing first on board the sloop of war Vincennes he also commanded the schooner Sea Gull for the first Antarctic voyage in 1839. During the expedition, Johnson was sent on several surveying ventures including the overland survey of the Cascade Range in North America. This two-month expedition resulted in the production of a new map of the Oregon Territory. Johnson was arrested and charged with disobedience and wasting government property and became one of several members of the expedition to face a court martial its return in 1842. He was acquitted after a two-day trial. During the expedition Johnson had served on four of the six expedition ships.
From the guide to the Robert Johnson collection, 1838-1841, (Scott Polar Research Institute, University of Cambridge)