The capturing officer, in case he should bring his prize directly to the United States, ought to be required to land the negroes in some one or more ports, to be designated by Congress, where the prevailing health throughout the year is good.  At these ports cheap but permanent accommodations might be provided for the negroes until they could be sent away, without incurring the expense of erecting such accommodations at every port where the capturing officer may think proper to enter.  On the present occasion these negroes have been brought to Key West, and, according to the estimate presented by the marshal of the southern district of Florida to the Secretary of the Interior, the cost of providing temporary quarters for them will be $2,500 and the aggregate expenses for the single month of May will amount to $12,000.  But this is far from being the worst evil.  Within a few weeks the yellow fever will most probably prevail at Key West, and hence the marshal urges their removal from their present quarters at an early day, which must be done, in any event, as soon as practicable.  For these reasons I earnestly commend this subject to the immediate attention of Congress.  I transmit herewith a copy of the letter and estimate of Fernando J. Moreno, marshal of the southern district of Florida, to the Secretary of the Interior, dated 10th May, 1860, together with a copy of the letter of the Secretary of the Interior to myself, dated 16th May.

It is truly lamentable that Great Britain and the United States should be obliged to expend such a vast amount of blood and treasure for the suppression of the African slave trade, and this when the only portions of the civilized world where it is tolerated and encouraged are the Spanish islands of Cuba and Porto Rico.

JAMES BUCHANAN.

WASHINGTON, May 22, 1860.

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.

WASHINGTON, May 22, 1860.

To the House of Representatives: