HEADQUARTERS FORT JEFFERSON, TORTUGAS, January 23, 1861. SIR: I have the honor to report for the information of the General-in-Chief that I found on my arrival here, notwithstanding the energetic, well-directed, and highly-commendable efforts of Captain Meigs, the Engineer in charge, that Fort Jefferson could not be successfully defended from a judiciously-planned and concerted attack [...]