One of the remarkable features of the Sonora Campaign was the wonderful manner in which the Federals after each battle, left behind ammunition, guns and equipment which the Constitutionalists so badly needed. The reply of the Constitutional chiefs to their complaining soldiers usually was: “Never mind, boys, Huerta himself will give us arms and ammunition to fight him with.” This statement has proved true all through the revolt. Before the Constitutionals had a chance to recover from the hardships of the Naco victory, a still greater danger threatened them. A strong force of Federals, four thousand in number, well-equipped, was coming from the south by way of the Pacific coast, General Luis Medina Barron was in charge of them. Before leaving Guaymas, he pledged on his “military honor” that he would be in Hermosillo in fifteen days. He said he would have the head of Obregon stuck upon the point of his sword and that he would banquet at the Hotel Arcadia. But the Constitutional chiefs were not frustrated by the boastings of General Barron, and quickly reorganizing their army, they took positions between Ortiz and Guaymas at Santa Rosa, a flag station on the Southern Pacific Railroad of Mexico. Confident of their ultimate victory, the Federals marched towards the Constitutionalists. Early in the morning of the 9th of May they opened a vigorous fire. The attack lasted three days. The Constitutionalists realizing the value of the springs and wells in that torrid zone, fought desperately for their possession. Once the water supply was captured, it meant the defeat of the Federals. On the second day of the battle, this was accomplished and the Federals were forced back to the Railroad tanks, which could supply them with water no longer than one day. After the third day’s fighting, the Federals, worn out with thirst, retired, leaving a large number of dead and wounded. In their hasty retreat they left behind a great quantity of armaments and provisions. The boasting General Barron escaped to Guaymas, wounded by the enemy, while many of his chiefs were taken to Hermosillo as prisoners of war. While Obregon was fighting against General Barron, General Hill had not remained idle. He was appointed to carry on operations in the southern part of the State. This he accomplished admirably, especially the wiping out of the “Battalion of Death.” This battalion carried a black flag, with a skull and cross bones upon it and their method was to terrorize the townspeople by killing innocent women and children. When they met General Hill in open battle they were completely wiped out.