Burning of the Dry Dock at Pensacola.
--The Pensacola Observer, of Tuesday last, says ‘"the dry dock, originally intended to have been sunk in the channel, to obstruct the passage of war steamers into our harbor, but which from necessity, not choice, was sunk in the bay, about midway between Pickens and the Yard, was burned to the water's edge last night. Who the perpetrators of the act were, is solely a question of speculation, as we go to press; though, the Yankees have the general credit of it. Upon this point, however, we soon will be fully sulightened, but upon the point that we have lost ever half a million of dollars by the operation, our mind is perfectly clear and settled,"’