From Washington.
movements of troops.
arrest of spies.
Alexandria to be occupied by Federal troops.
Lincoln Visits the Navy-Yard.
&c., &c., &c.
Alexandria, May 5.
--There are now 6,000 troops at Annapolis.
Seven hundred left there last night, bound out. They are to land near Baltimore, to co-operate with troops approaching that city from the North.
Several persons have been arrested in the neighborhood of Annapolis, as spies.
Some had made accurate survey and minute details of the operations there.
The sloop-of-war Allegheny, the Forward, the Baltic, and the Kedar, are off Annapolis.
Travel between Perryville and Annapolis is uninterrupted; twelve steamers are on the route.
The railroad between Annapolis and Washington is guarded by Federal troops.
It is supposed the Baltimore and Ohio Railroad will soon be made a military road.
[Second Dispatch.]
Alexandria, May 5.
-- This city, it is expected, will be occupied by Federal troops tomorrow, who will advance from Washington by the Long Bridge.
Two transports, with men and munitions, passed up to Washington to-day.
Lincoln visited and inspected the Navy-Yard to-day. 