Charles Francis Adams, U.S. minister to Great Britain, threatens war unless the British honor their neutrality and stop construction on a warship allegedly being built for the Confederacy.
Federal forces continue bombarding the fortifications in Charleston Harbor, South Carolina, in preparation for another infantry attack.
The experimental Confederate submarine H.L. Hunley sinks in Charleston Harbor, South Carolina.
The Federal bombardment of Fort Sumter and Batteries Wagner and Gregg in Charleston Harbor, South Carolina, temporarily halts.
Federal heavy artillery opens fire on Fort Sumter in Charleston Harbor, South Carolina, while Federal naval vessels begin bombarding Battery Wagner on Morris Island to the south.
Federal army-navy forces continue working to capture Morris Island at the southern entrance to Charleston Harbor, South Carolina.