SIR: I have the honor, by direction of the President, to acknowledge the receipt of the letter addressed to him by your excellency on the 18th instant, advising him that Ebenezer S. Greely, esq., a citizen of Maine, while employed within its limits and under its authority in taking an enumeration of the inhabitants of the county of Penobscot, has been arrested a second time by the provincial authorities of New Brunswick, and is now in confinement in the jail at Frederickton; and requesting that prompt measures be adopted by the Government of the United States to effect the release of Mr. Greely. I hasten to assure you in reply that Mr. Stevenson, the minister of the United States at London, will be immediately instructed to renew his application to the British Government for the release of Mr. Greely, and that the result, when obtained and communicated to this Department, will be made known to your excellency without unnecessary delay. Information was given at an early day to the executive of Maine of the informal arrangement between the United States and Great Britain in regard to the exercise of jurisdiction within the disputed territory, and the President's desire was then expressed that the government and people of that State would cooperate with the Federal Government in carrying it into effect. In the letter addressed to your excellency from this Department on the 17th ultimo you were informed of the continuance of that arrangement and of the reasons for it. I am now instructed by the President (who indulges the confident expectation that the executive of Maine will still see in the gravity of the interests involved a sufficient motive for his cordial concurrence in an arrangement which offers the best prospect of an amicable and satisfactory adjustment of the general question of boundary) to request your excellency's cooperation in the conciliatory course adopted by the two Governments, an adherence to which seems the more important at this time from the consideration that an answer to the President's last proposition is daily looked for, and to renew to you the assurance that no efforts shall be spared on his part to bring the negotiation to a speedy conclusion. I have the honor to be, etc., JOHN FORSYTH. _Mr. Forsyth to Mr. Stevenson_. [Extract.] DEPARTMENT OF STATE, _Washington, July 12, 1837_. ANDREW STEVENSON, Esq., etc.