APRIL 10TH, 1861: Robert Anderson to Col. L. Thomas, Adjutant General, U.S. Army.
Reported about the cessation of mail and that their last mail bag had been returned from Fort Johnson.
The South Carolinians had been hard at work strengthening fortifications and "that the parapets and traverses have been both heightened and strengthened.
"Last the night the guard-boats, of which we saw eight on duty, were very diligent guarding all the channels, and we see signal vessels very far out beyond the bar. The garrisons of Castle Pinckney and Fort Johnson, and the batteries on Morris Island, have been strengthened yesterday and this morning."
A fourth gun has been mounted in a new battery on Sullivan's Island which can stop any boat landing on the left side of the fort and can drive the Sumter garrison from the guns en barbette. "All we can do after that will be to use the guns of the lower tier."
Anderson and his men are doing all they can to prepare for an attack.