On the 2d of September, 1861, Mr. Seward, in a despatch to Mr. Corwin, at Mexico, announced that the President greatly desired the political status of Mexico as an independent nation to be permanently maintained; that the events communicated by Mr. Corwin alarmed him, and he conceived that the people of the United States would scarcely justify him, were he to make no effort for preventing so great a calamity on this continent as would be the extinction of that neighbor republic; that he had therefore empowered Mr. Corwin to negotiate a treaty with Mexico for the assumption by the United States of the interest, at three per cent, upon the funded debt of that country, the principal of which was understood to be about sixty-two millions of dollars, for the term of five years from the date of the decree recently issued by Mexico suspending such payment, provided that Mexico could pledge to the United States its faith for the reimbursement of the money, with six per cent interest, to be secured by special lien upon all the public lands and mineral rights in the several Mexican States of Lower California, Chihuahua, Sonora, and Cinaloa, the property so pledged to become absolute in the United States at the expiration of the term of six years from the time when the treaty went into effect, if such reimbursement were not made before that time. The President felt that this course was rendered necessary by circumstances as new as they are eventful, and seeming to admit of no delay. Mr. Seward proceeds to say, that his instructions are conditional upon the consent of the British and French Governments to forbear action against Mexico, on account of failure or refusal to pay the interest in question, until after the treaty had been submitted to the Senate, and, if ratified, then so long thereafter as the interest is paid by the United States. Mr. Seward adds, that his instructions are not to be considered as specific, but general, subject to modification as to sums, terms, securities, and other points. Mr. Corwin, in an earlier despatch, dated at Mexico, 29th July, 1861, and addressed to Mr. Seward, had already suggested the policy he was now authorized to pursue, and proposed a lien on the public lands and mineral rights in the provinces mentioned by Mr. Seward. From such arrangement, in his opinion, two consequences would follow: first, all hope of extending the domain of a separate Southern republic in this quarter or in Central America would be extinguished; and, secondly, any further attempt to establish European power on this continent would cease to occupy either England or Continental Europe.