From Washington.
Washington, March 22.
--The rumors of the contemplated evacuation of Fort Sumter, are now believed to have been put forth for political effect.
It is positively certain, however, that it will be shortly abandoned; and it is equally certain that Fort Pickens will not be reinforced.
On demand of Col. A. M. Barbour, the Secretary of War has promised shortly to withdraw the Federal guard now stationed at Harper's Ferry.
The President has submitted to the Senate, for their advice, the proposition of Great Britain to refer the San Juan question to the arbitration of Sweden, the Netherlands, or Switzerland.
It is stated on the streets to-night, that the President by advice of the Cabinet, has sent a special messenger to Richmond, in consequence of reports that Virginia was about to secede.
Can't verify it to-night. 