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. In 1863, Union forces secured a foothold in northern Alabama in spite of the opposition of General Nathan B. Forrest. From 1861, the Union blockade shut Mobile, and, in 1864, the outer defenses of Mobile were taken by a Union fleet; the city itself held out until April 1865. Alabama soldiers fought in hundreds of battles; the state's losses at the Battle of Gettysburg were the highest loss of any battle with 1,750 dead plus more captured or wounded; the "Alabama Brigade" took 781 casualties. Governor Lewis E. Parsons in July 1865 made a preliminary estimate of losses, which totaled that around the 122,000 Alabamian soldiers who served, around 35,000 died during the war. The next year Governor Robert M. Patton estimated that 20,000 veterans had returned home with permanent disabilities. With cotton prices low, the value of farms shrank, from $176 million in 1860 to only $64 million in 1870. The livestock supply shrank too, as the number of horses fell from 127,000 to 80,000, and mules from 111,000 to 76,000. The overall population growth remained the same, the growth that might have been expected was neutralized by death and emigration out of the state. Reconstruction (1865–1875) According to the Presidential plan of reorganization, a provisional governor for Alabama was appointed in June 1865. A state convention met in September of the same year, and declared the ordinance of secession null and void and slavery abolished. A legislature and a governor were elected in November, and the legislature was at once recognized by President Andrew Johnson, but not by Congress, which refused to seat the delegation. Johnson ordered the army to allow the inauguration of the governor after the legislature ratified the Thirteenth Amendment in December 1865. But the legislature's passage of Black Codes to control the freedmen who were flocking from the plantations to the towns, and its rejection of the Fourteenth Amendment to grant suffrage, intensified Congressional hostility to the Presidential plan. In 1867, the congressional plan of Reconstruction was completed and Alabama was placed under military government. The freedmen were enrolled as voters. Only whites who could swear the Ironclad oath could be voters; that is they had to swear they had never voluntarily supported the