WASHINGTON, D. C., March 15, 1864.

Major-General POPE,

Milwaukee:

Orders were issued some days ago to provost-marshal in regard to the enlistment of scouts by General Sully. Does Brackett's Minnesota Battalion, formed out of the Fifth Iowa Cavalry, constitute any part of your intended Indian expedition? It appears from papers in the War Department that it was intended to be sent South. Please answer.

H. W. HALLECK,

Major-General, Chief of Staff.

HEADQUARTERS DEPARTMENT OF THE NORTHWEST,
Milwaukee, Wis., March 15, 1864.

The following instructions for operations in the Indian country during he season of 1864 are furnished for the information and guidance of Generals Sully and Sibley: It is proposed to establish the following posts: First. A post of four companies of infantry and five companies of cavalry on the south side of Devil's Lake and as near as convenient to the western extremity of the lake. Second. A post of four companies of infantry and five companies of cavalry on james River, at a point as nearly as practicable due west of the head (or northern extremity) of the Coteau des Prairies. Third. A post of four companies of infantry and four companies of cavalry on the Missouri River, at or near the mouth of Long Lake. Fourth. A post (garrison to be determined hereafter) on the Yellowstone River, near the trading post of alexander, not more than 50 miles below the post.

The last three of these posts are so placed as to be nearly on the proposed emigrant route to Idaho from the upper Mississippi and Missouri Rivers, and well-marked trails between them should be opened as soon as possible. In connection with the establishment of these posts a campaign will be made against the yanktonais Sioux north, and the Teton Sioux south, of the Missouri River by the combined cavalry forces of the department. As every indication and all information point to a combination of the Yanktonais Sioux with the powerful bands of the Unpapa and other Teton Sioux, and a concentration of these bands on the upper Missouri above Grand River, the following plan of operations will be pursued: General Sully, after providing for the security of the Iowa frontier and the frontier settlements in Dakota, will concentrate all his disposable force (say 1,300 cavalry, with the necessary light batteries) at Fort Pierre, and thence move up the Missouri River to the mouth of Bordache Creek. Four companies of infantry will follow his movement up the river on steam-boats, which will carry supplies for his command and for purposes hereafter to be specified.

General Sibley, after providing for the security of the Minnesota frontier, will dispatch all his disposable mounted force (not less than 1,600, with the necessary light batteries) to the Missouri at the mouth of Bordache Creek. He will place some trusty and experienced officer in command of this force, who will proceed to his destination by such route as General Sibley may designate. Upon reaching the vicinity of the Missouri River, he will report for duty to General Sully. As soon as possible after the departure of this force from