Thirty-nine Alabamians attained flag rank, most notably Lieutenant General James Longstreet and Admiral Raphael Semmes. Josiah Gorgas, who came to Alabama from Pennsylvania, was the chief of ordnance for the Confederacy. He located new munitions plants in Selma, which employed 10,000 workers until the Union soldiers burned the factories down in 1865. Selma Arsenal made most of the Confederacy's ammunition. The Selma Naval Ordnance Works made artillery, turning out a cannon every five days. The Confederate Naval Yard built ships and was noted for launching the CSS "Tennessee" in 1863 to defend Mobile Bay. Selma's Confederate Nitre Works procured niter for the Nitre and Mining Bureau for gunpowder, from limestone caves. When supplies were low, it advertised for housewives to save the contents of their chamber pots—as urine was a rich source of nitrogen.