Should you conquer and take possession of New Mexico and Upper California, or considerable places in either, you will establish temporary civil government therein, abolishing all arbitrary restrictions that may exist, so far as it may be done with safety.

In performing this duty, it would be wise and prudent to continue in their employment all such of the existing officers as are known to be friendly to the United States, and will take the oath of allegiance to them.  The duties of the custom-house ought, at once, to be reduced to such a rate as may be barely sufficient to maintain the necessary officers without yielding any revenue to the government.  You may assure the people of these provinces that it is the wish and design of the United States to provide for them a free government with the least possible delay, similar to that which exists in our territories.  They will then be called on to exercise the rights of freemen in electing their own representatives to the territorial legislature.  It is foreseen that what relates to the civil government will be a difficult and unpleasant part of your duty, and much must necessarily be left to your own discretion.  In your whole conduct you will act in such a manner as best to conciliate the inhabitants and render them friendly to the United States.

It is desirable that the usual trade between the citizens of the United States and the Mexican provinces should be continued, as far as practicable, under the changed condition of things between the two countries.  In consequence of extending your expedition into California it may be proper that you should increase your supply for goods to be distributed as presents to the Indians.  The United States superintendent of Indian affairs at St. Louis will aid you in procuring these goods.  You will be furnished with a proclamation in the Spanish language, to be issued by you and circulated among the Mexican people on your entering into or approaching their country.  You will use your utmost endeavors to have the pledges and promises therein contained carried out to the utmost extent.

I am directed by the president to say that the rank of brevet brigadier-general will be conferred on you as soon as you commence your movement toward California, and sent round to you by sea or over the country, or to the care of the commandant of our squadron in the Pacific.  In that way cannon, arms, ammunition and supplies for the land forces will be sent to you.

Very respectfully, your obedient servant,

W.L.  MARCY,

Secretary of War.

COLONEL S. N. KEARNEY, Fort Leavenworth, Missouri.