fire had jumped the river a second time and was now raging across the city's north side. Despite the fire spreading and growing rapidly, the city's firefighters continued to battle the blaze. A short time after the fire jumped the river, a burning piece of timber lodged on the roof of the city's waterworks. Within minutes, the interior of the building was engulfed in flames and the building was destroyed. With it, the city's water mains went dry and the city was helpless. The fire burned unchecked from building to building, block to block. Finally, late into the evening of October 9, it started to rain, but the fire had already started to burn itself out. The fire had spread to the sparsely populated areas of the north side, having thoroughly consumed the densely populated areas. Aftermath Once the fire had ended, the smoldering remains were still too hot for a survey of the damage to be completed for many days. Eventually, the city determined that the fire destroyed an area about long and averaging wide, encompassing an area of more than . Destroyed were more than of roads, of sidewalk, 2,000 lampposts, 17,500 buildings, and $222 million in property, which was about a third of the city's valuation in 1871. On October 11, 1871, General Philip H. Sheridan came quickly to the aid of the city and was placed in charge by a proclamation, given by mayor Roswell B. Mason: "The Preservation of the Good Order and Peace of the city is hereby intrusted to Lieut. General P.H. Sheridan, U.S. Army."To protect the city from looting and violence, the city was put under martial law for two weeks under Gen. Sheridan's command structure with a mix of regular troops, militia units, police, and a specially organized civilian group "First Regiment of Chicago Volunteers." Former Lieutenant-Governor William Bross, and part owner of the Tribune, later recollected his response to the arrival of Gen. Sheridan and his soldiers: "Never did deeper emotions of joy overcome me. Thank God, those most dear to me and the city as well are safe." For two weeks Sheridan's men patrolled the streets, guarded the relief warehouses, and enforced other regulations. On October 24 the troops were relieved of their duties and the volunteers were mustered out of service. Of the approximately 324,000 inhabitants of Chicago in 1871, 90,000 Chicago residents (1 in 3 residents) were