In May 1836, an act of Congress authorized the President to establish the five year United States Exploring Expedition "to the Pacific Ocean and South Seas", the first extra-continental American scientific exploration. Jones was appointed Commander of the Expedition. Delays in Expedition departure dates, and various other disagreements, led to Jones (and certain scientists, including botanist Asa Gray) declining the position in December 1837. The position was subsequently offered to Charles Wilkes.