HEADQUARTES DEPARTMENT OF THE MISSOURI,

Sait Louis, January 14, 1862.

Major General GEORGE B. McCLELLAN,

General-in-Chief of the Army, Washington.

GENERAL: Advices received from scouts and spies who have been in the enemy's lead to the belief that Price's pretended retreat

was a ruse intended to deceive us. He fell back rapidly from Osceola to Springfield giving out the report that he was intending to retire to winter quarters in Arkansas. It was expected that on receiving information of this retreat we would withdraw the mass of our forces at Rolla and Sedalia for operations against Columbus. As soon as this had been done Price was to return with re-enforcements from Arkansas and march rapidly to Lexington and Jefferson City. In the meantime his emissaries were to destroy all railroad bridges and telegrph lines so as to prevent our sending troops against him. This city was at the same time to be set on fire at different places and a general insurrection was to break out here and in all the northern counties of this State. The time of the burning of the bridges was determined by private signals of which we have discovered thousands scattered through the country. Fortunately I was warned in time to protect this city and the principal bridges. Much damage however, has been done at places where it was least expected, as near Quincy, Palmyra, Hudson, Mexico, &c., almost under the noses of our troops. At other places my telegrams were received in time to save the bridges. Eidences of this plan of the enemy have been received from so many sources as to leave very little doubt of its correctness.

The arrangements made to break up the bands of bridge-burners in the northeastern counties of the State have been very successful. Immediately after the burning had commenced a small force of cavalry started in the cas from Hudson City. In this way they surprised a large party of secessionists, killed 8, took a number of prisoners, horses, &c. On the 28th ultimo General Prentiss with 240 of Colonel Glover's cavalry and 200 of Colonel Birge's sharpshooters attacked a body of rebels under Colonel Dorsey about 900 strong at Mount Zion, Boone County, and dispersed them. Enemy's loss reported 159 killed and wounded, 35 prisoners, 95 horses, and 105 guns captured. Our loss 3 killed and 11 wounded. This disparity resulted from the long range of the rifles of our sharpshooters.

Several other skirmishes have taken place and some 20 prisoners taken. Brigadier-General Schofield captured about 50 in the vicinity of Mexico. The enemy has scattered in every direction but as our troops are scouring the country thoroughly I think many of the bridgeburners will eventually be caught. Most of them are from Price's army and have returned home under the pretense that they were Union men impressed into Price's service. No reliance whatever can be placed upon these pretended refugees from military impressment.

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Very respectfully, your obedient servant,

H. W. HALLECK,

Major-General.

17 R R-SER II, VOL I