CAIRO, April 12, 1863.

General ROSECRANS:

Marine Brigade will leave here to-night or to-morrow morning, it is not composed of gunboats, but of river boats, musket-proof. Brigade consists of one regiment of infantry, one squadron of cavalry, and one battery of light artillery, four guns, and is intended to act promptly against small bands near river banks, and in co-operation with gunboats. General Ellet has special instruction for his guidance from Admiral Porter. Have given General Ellet a copy of your dispatch.

A. M. PENNOCK,

Fleet Captain and Commanding.

GENERAL ORDERS,
HDQRS. DEPT. OF THE CUMBERLAND,

No. 78. Murfreesborough, Tenn., April 12, 1863.

The following allowance of tents is prescribed for the troops of this army, in active service in the field:

For the headquarters of an army corps, division, or brigade, one wall tent for the commanding general, and one for every two officers of his staff; for the field and staff officers of every regiment, three wall tents; for the sick of every regiment, one hospital tent; for regimental hospital stores, one wall tent; for every company of infantry and cavalry, one wall tent; for every battery of artillery, two wall tents; for every commissioned line officer, one shelter tent; for every two non-commissioned officers, soldiers, officers' servants, and authorized camp followers, one shelter tent.

There will be allowed for office purpose-for the headquarters of an army corps, one hospital and four wall tents; for the headquarters of a division, four wall tents; for the headquarters of a brigade, three wall tents.

Where regiments are supplied with other than wall tents, the allowance prescribed by this order for companies and for hospital stores will be retained from the tents belonging to the regiment.

The allowance of tents to companies and batteries is prescribed, in order to provide a place in which the company books and papers may be properly kept. Commanding officers will, therefore, see that these tents are not used for any purpose which will interfere with that contemplated in these orders.

All the ten tag of this army, in excess of this allowance, will be immediately packed and made ready for storage. Each tent will be plainly marked with the name of the regiment to which it belongs, and packed in such a manner that the mark can be readily seen.

By command of Major-General Rosecrans:

C. GODDARD,

Assistant Adjutant-General.

WAR DEPARTMENT,

Washington, April 12, 1863-10.30 a.m.

Major-General BURNSIDE,

Cincinnati, Ohio:

It will not be possible to furnish at present armaments for all the forts contemplated by you. Fortifications must, as a general rule, be constructed by the troops and contrabands.

H. W. HALLECK,

General-in-Chief.