The following is an extract from a letter written by an officer on board the United States ship Colorado:
"On the night of the 3d of August we were sent by the flag-officer into Pensacola harbor to reconnoitre and, if possible, capture some of the schooners or steamers of the rebels. We started from the ship as soon after dark as our movements would be obscured, and concealed from the numerous glasses and telescopes constantly pointed at us from the forts and works of secessiondom, passed into the harbor with five boats, Capt. BAILEY, of the Colorado, who commanded, leading in his light gig, without being observed by the rebel forts or batteries. The night was dark, and after rowing about the harbor and finding that there were no vessels anchored off that we could prey upon, we pulled in for the "Navy-yard," which, perhaps you have heard, is defended by a strong battery. Treating the rebels sentries' hails of "Boat ahoy, who comes there?" with silent contempt, we pulled steadily in with the boats. Leaving them off the pier end, the Captain went in the slip with his gig to see what could be done; found a schooner tied up to the wharf by the guard-house and a guard of soldiers mustering on the wharf by her. The long roll was being beaten, and a general mustering of rebel forces, together with sending up of rockets and a fire balloon as a signal of attack. We thought it prudent to retire, which we did, with the boats, without a shot being fired on either side. We knew or were informed previously at 'Pickens,' that the wharf where we found the schooner was defended by two 32-pounders and two howitzers, but wore in hopes to have found the schooner tied up somewhere else than at the wharf immediately alongside of the guard-house, where we could not burn her without lighting up the whole harbor and sacrificing our boats to their point blank fire. As it was, we gave the rebels a terrible fright, and as we retired we could hear the long roll beat and see the batteries all lit up from the Navy-yard to Fort Barrancas. We do not intend to let Gen. BRAGG send all his troops to Manassas with impunity. He must keep at least five thousand men here to make his position a safe one, for the fleet, the Regulars and the 'pet lambs' are all watching him with deep interest."