To the Senate: 

The importance of the subject to the tranquillity of our country makes it proper that I should communicate to the Senate, in addition to the information heretofore transmitted in reply to their resolution of the 17th of January last, the copy of a letter just received from Mr. Fox, announcing the determination of the British Government to consent to the principles of our last proposition for the settlement of the question of the northeastern boundary, with a copy of the answer made to it by the Secretary of State.  I can not doubt that, with the sincere disposition which actuates both Governments to prevent any other than an amicable termination of the controversy, it will be found practicable so to arrange the details of a conventional agreement on the principles alluded to as to effect that object.

The British commissioners, in their report communicated by Mr. Fox, express an opinion that the true line of the treaty of 1783 is materially different from that so long contended for by Great Britain.  The report is altogether ex parte in its character, and has not yet, as far as we are informed, been adopted by the British Government.  It has, however, assumed a form sufficiently authentic and important to justify the belief that it is to be used hereafter by the British Government in the discussion of the question of boundary; and as it differs essentially from the line claimed by the United States, an immediate preparatory exploration and survey on our part, by commissioners appointed for that purpose, of the portions of the territory therein more particularly brought into view would, in my opinion, be proper.  If Congress concur with me in this view of the subject, a provision by them to enable the Executive to carry it into effect will be necessary.

M. VAN BUREN.

Mr. Fox to Mr. Forsyth.

WASHINGTON, June 22, 1840.

Hon. JOHN FORSYTH, etc.: 

The undersigned, Her Britannic Majesty’s envoy extraordinary and minister plenipotentiary, has the honor to transmit to the Secretary of State of the United States, by order of his Government, the accompanying printed copies of a report and map which have been presented to Her Majesty’s Government by Colonel Mudge and Mr. Featherstonhaugh, the commissioners employed during the last season to survey the disputed territory.

The undersigned is instructed to say that it will of course have become the duty of Her Majesty’s Government to lay the said report and map before Parliament; but Her Majesty’s Government have been desirous, as a mark of courtesy and consideration toward the Government of the United States, that documents bearing upon a question of so much interest and importance to the two countries should in the first instance be communicated to the President.  The documents had been officially placed in the hands of Her Majesty’s Government only a few days previously to the date of the instruction addressed to the undersigned.