KANSAS CITY, March 24, 1862.

Hon. E. M. STANTON, Secretary of War:

Major Donaldson is here en route to Washington. Furnishes the following:

Santa Fe evacuated on the 5th. Troops and supplies withdrawn to Fort Union. Colonel Slough, of Colorado, arrived at Fort Union with 950 men, making total strength of that place 1,500. They would from junction with Colonel Canby. Colonel Canby was at Fort Craig on 7th, with 800 regulars and about same number Mexicans, with supplies for sixty days. Advance guard of Texans was at Algodones, 45 miles from Santa Fe, on 4th instant. Another battle expected before April 1.

JAS ROBERTS.

CONSULATE OF THE UNITED STATES OF AMERICA, Matamoros, March 24, 1862.

Hon. W. H. SEWARD,

Secretary of State, Washington, D. C.:

SIR: * * * In a conversation with the colonel commanding this line he informed me that a force was being organized of Mexicans on the Texas side to capture Matamoros, and that many Texans were joining, and that the real object was the capture of all the Americans on this side, and on observing everything in relation to it I find such to be the facts without a doubt.

The colonel here (Colonel Quiroyo), who is a warm advocate of the Union, and has been throughout the war, has assured me that he will protect all American citizens in Matamoros to the extent of his power, and for my personal safety and the safety of my documents he has several times offered me apartments in his own quarters, but as I have a small force of true Americans constantly around me I have declined, thinking that I can fight my way out if attacked.

A collision is becoming more imminent every day, and hundreds of heartfelt wishes are uttered both by Americans and Mexicans that a Government force my appear at Brazos Santiago and restore order.

The Texan troops are becoming demoralized and disorderly in the extreme, declaring that they will burn and destroy everything of both friend and foe.

A force of 1,000 men could conquer the entire line of the Rio Grande, as most of the German and the old United States soldiers would immediately turn at sight of the Union flag.

The difficulty in our mail facilities being now obviated and a regular line being established to Tampico, I am relieved of the expenses of my own courier, my great difficulty now being in procuring stationery.

I am, sir, very respectfully, your most obedient,

L. PIERCE, JR.,

United States Consul.

[MARCH 28, 1862.- For Halleck to Secretary of War,in reference to re-enforcements for New Mexico, see Series I, Vol. VIII, p.647.]

EXECUTIVE DEPARTMENT, Las Vegas, N. Mex., March 30, 1862.

Hon. W. H. SEWARD,

Secretary of State, Washington City:

SIR: In my communication of the 23rd instant I informed you that