Wak Depaütmknt, Aug. 30 Gen. Burnside commauds 11 3 own corps, except those temporarily datatclud and assigncd lo Gen Popo. Gen. McClellan BOiamanás tliat portion of the army of the Potomac that has not been sent FErward to Gen. Popu's oommaud. Gen. Popó commanda the army of Virginia, atid the forcea tcuiporurily attached to it. The forces are under coramand of General Halleek, General in Ohief. (Signed) E.D. TOWNSEND.A A.G.