Public considerations alone have induced me to withhold the dispatches of Mr. McLane addressed to the Secretary of State.  I concur with the Secretary of State in the views presented in his report herewith transmitted, against the publication of these dispatches.

Mr. McLane has performed his whole duty to his country, and I am not only willing, but anxious, that every Senator who may desire it shall have an opportunity of perusing these dispatches at the Department of State.  The Secretary of State has been instructed to afford every facility for this purpose.

JAMES K. POLK.

WASHINGTON, July 21, 1846.

To the Senate of the United States: 

I communicate herewith a report from the Secretary of State, in answer to the resolution of the Senate of the 18th of June, 1846, calling for certain information in relation to the Oregon Territory.

JAMES K. POLK.

WASHINGTON, August 4, 1846.

To the Senate of the United States: 

I herewith communicate to the Senate the copy of a letter, under date of the 27th ultimo, from the Secretary of State of the United States to the minister of foreign relations of the Mexican Republic, again proposing to open negotiations and conclude a treaty of peace which shall adjust all the questions in dispute between the two Republics.  Considering the relative power of the two countries, the glorious events which have already signalized our arms, and the distracted condition of Mexico, I did not conceive that any point of national honor could exist which ought to prevent me from making this overture.  Equally anxious to terminate by a peace honorable for both parties as I was originally to avoid the existing war, I have deemed it my duty again to extend the olive branch to Mexico.  Should the Government of that Republic accept the offer in the same friendly spirit by which it was dictated, negotiations will speedily commence for the conclusion of a treaty.

The chief difficulty to be anticipated in the negotiation is the adjustment of the boundary between the parties by a line which shall at once be satisfactory to both, and such as neither will hereafter be inclined to disturb.  This is the best mode of securing perpetual peace and good neighborhood between the two Republics.  Should the Mexican Government, in order to accomplish these objects, be willing to cede any portion of their territory to the United States, we ought to pay them a fair equivalent—­a just and honorable peace, and not conquest, being our purpose in the prosecution of the war.