HEADQUARTERS U. S. FORCES ON THE RIO GRANDE,
Brownsville, Tex., February 4, 1864.

Brigadier General CHARLES P. STONE,

Chief of Staff:

GENERAL: By this mail I send you papers from the interior of Texas; nothing very late, but at the same time containing some items of interest. From spies and refugees I have late and reliable information from that portion of the State west of the San Antonio River. The enemy's force in this section is as follows: 100 men under Captain Weyman, at Eagle Pass; 300 with Colonel Benavides, one-half of them at Laredo, on the Rio Grande, the other half at Fort Ewell, on the Nueces River; 200 under Captains Rabb and Doty, on the Nueces, between San Patricio and Oakville, and 300 militia at San Antonio, 250 of whom are Union men, and will join us when a little nearer their homes. This estimate of their numbers can be relied upon, as it has been corroborated in many ways.

Occasional small scouting parties have been down as far as King's ranch, 120 miles from here, but none nearer. I have two scouting parties out at the present time, one up the Rio Grande, and another, under Colonel Haynes, in the direction of Corpus Christi. Deserters state in the most positive manner that the only rebel troops between the Colorado and San Antonio Rivers are those of Colonel Ford's regiment, about 500 in all, some of whom are at Victoria, and a few at Texana and Goliad. The main body are on the Canney, with headquarters at McNeil's plantation. The most reliable statements fix the total number of Magruder's force at 15,000 regulars and militia.

I have advices from Mr. McManus, at Piedras Negras, about whom I have written in former letters. Up to January 12 he had sworn in 40 men, over 30 of whom crossed the river and at once re-enlisted in Weyman's company at Eagle Pass. The design was to have his men join the rebel force, and at the proper time revolt. This they expected to be ready to do on the night of the 14th of January. McManus is very decided as to his capability of holding the pass, and expects to have 200 men as soon as it is known that he holds that place. Recruits are constantly being sent from Monterey to join him. I have another man at a point in Mexico opposite Laredo operating in the same way, but have nothing late from him. McManus wrote me under date of the 12th ultimo that within twenty days 52 rebel officers had crossed into Mexico, many of whom are on their way out of the country. Among them he said was Major-General Hindman, but this I think is a mistake. Matters in Brownsville are quiet. The health of the troops is fair, although we have had a great many light cases of small-pox.

I have the honor to be, with great respect, your obedient servant,

F. J. HERRON,

Major-General, Commanding.

HDQRS. FIRST DIVISION, THIRTEENTH ARMY CORPS,
Indianola, Tex., February 4, 1864.

Colonel C. L. HARRIS,

Commanding Second Brigade:

COLONEL: I send you inclosed Special Orders, Numbers 16, for your information. During the absence of the detachment alluded to in this order you will please keep your brigade well on the alert, and as