I transmit herewith a communication from the Secretary of the Interior of the 12th instant, with accompanying papers, in relation to coal lands upon the San Carlos Reservation, in the Territory of Arizona. The subject is presented for the consideration of Congress. CHESTER A. ARTHUR. EXECUTIVE MANSION, _April 17, 1882_. _To the Senate_: I transmit herewith a report from the Secretary of State and its accompanying papers, concerning the international regulations for preventing collisions at sea, and I earnestly commend this important subject to the early and favorable consideration of Congress. CHESTER A. ARTHUR. [The same message was sent to the House of Representatives.] EXECUTIVE MANSION, _April 18, 1882_. _To the Senate and House of Representatives_: I send herewith a copy of the circular invitation extended to all the independent countries of North and South America to participate in a general congress to be held in the city of Washington on the 22d of November next for the purpose of considering and discussing the methods of preventing war between the nations of America. In giving this invitation I was not unaware that there existed differences between several of the Republics of South America which would militate against the happy results which might otherwise be expected from such an assemblage. The differences indicated are such as exist between Chile and Peru, between Mexico and Guatemala, and between the States of Central America. It was hoped that these differences would disappear before the time fixed for the meeting of the congress. This hope has not been realized. Having observed that the authority of the President to convene such a congress has been questioned, I beg leave to state that the Constitution confers upon the President the power, by and with the advice and consent of the Senate, to make treaties, and that this provision confers the power to take all requisite measures to initiate them, and to this end the President may freely confer with one or several commissioners or delegates from other nations.. The congress contemplated by the invitation could only effect any valuable results by its conclusions eventually taking the form of a treaty of peace between the States represented; and, besides, the invitation to the States of North and South America is merely a preliminary act, of which constitutionality or the want of it can hardly be affirmed. It has been suggested that while the international congress would have no power to affect the rights of nationalities there represented, still Congress might be unwilling to subject the existing treaty rights of the United States on the Isthmus and elsewhere on the continent to be clouded and rendered uncertain by the expression of the opinions of a congress composed largely of interested parties.