From Washington.
Washington, Aug. 17
--It is proposed to burn all the woods on the banks of the Potomac, to prevent the constant disasters to the Federals from concealed Southerners.
Heavy firing was heard to-day in the direction of Aquia Creek.
It is stated that Minister Faulkner was arrested as a hostage for Messrs. Ely, McGraw and others.
No non-combatants are prisoners.
Quartermaster Melggs has gone to New York, to investigate clothing contracts.
The Contract Committee are making astonishing discoveries.
The Pawnee exchanged a few harmless shots this forenoon at Aquia Creek.
President Lincoln has issued a proclamation declaring all commercial intercourse with the seceded States unlawful.
Goods going to or coming from them, either by land or water, without Secretary Chase's special permit, will be forfeited, and vessels or vehicles conveying the same will also be forfeited, and all persons engaged will be arrested, and travel from North to South is interdicted.
From and after fifteen days from the publication of the proclamation, all vessels or ships, belonging in whole or in part to citizens or inhabitants of the seceded States, found at sea, or in any of the United States ports, will be forfeited.
Books for subscriptions to the loan will be opened in all the cities and towns in the United States.
A letter from Martinsburg reports that the Confederate cavalry are constantly killing the Federal pickets.
The correspondent of the N. Y. Tribune, says that many of the disasters to our various regiments was in consequence of the mutiny among the three months volunteers who refused to go to Tortugas.
The Herald's correspondent says that numberless incidents go to show that the Confederates are on the eye of attacking the Federal ones.
The Baltimore Secessionists have received intelligence that the Confederates are gradually working their way towards Washington.
Gen. Scott doubts this, but Gen. McClellan, who pretends to know Gen. Beauregard's mode of combination, anticipates an early attack from some point on the Potomac. 