To the Senate and House of Representatives:
I transmit herewith the copy of a letter, dated yesterday, from the Secretary of the Interior, communicating the copy of a letter addressed to him on the 13th instant by Fernando J. Moreno, marshal of the southern district of Florida. From this it appears that Lieutenant Stanly, of the United States steamer Wyandotte , captured the bark William, with about 550 African negroes on board, on the south side of Cuba, near the Isle of Pines, and brought her into Key West on the 12th instant. These negroes have doubtless been delivered to the marshal; and with those captured on board the Wildfire will make the number in his custody about 1,000. More may be daily expected at Key West, which, both on account of a deficiency of water and provisions and its exposure to yellow fever, is one of the worst spots for an African negro depot which could be found on the coast of the United States.
James Buchanan, Special Message Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/201986