<p>Adolphus W. Greely, a veteran of the Civil War, rose from private in that conflict to become a brigadier general, and Chief Signal Officer of the reconstituted Signal Corps on 1 July 1891. Greely was progressive; one of the first actions of his new command was to create a balloon section, the first true military aeronautical activity in US history. (Civil War balloonists all were hired as civilians, and never were commissioned in the Union Army.)
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<p>When the United States and Spain went to war in April 1898, the Signal Corps' sole balloon was in dead storage in Denver, and there were no trained personnel to rehabilitate it and get it operational. Under the urgency of war, Corps personnel did manage to get the balloon repaired by mid-May, and to Daiquiri, Cuba, by 28 June. The following day the detachment reached their headquarters and prepared for the first ascent.
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<p>The balloon was a mess, with its varnished envelope stuck together in places from the humidity. But it was inflated, and three ascents were made, one of them confirming the presence and position of the main Spanish battle fleet in Santiago harbor.
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<p>On 1 July, the balloon was moved toward El Poso Hill, and made its first ascent. The two observers, Lieutenant Colonels. Joseph E. Maxfield and George McC. Derby, saw American units on the advance, but could not make out the Spanish forces because thick woods blocked their view from that position. The balloon was hauled down partway and moved nearer to San Juan Hill. On the way, its manoeuvring lines were fouled by trees and shrubs, and the balloon could not get enough altitude either for safety or for observation. Even so, the first ascent from the new location revealed the position and strength of the entrenched Spanish forces. American artillery was swung to bear on them and to support the American advance up the hill.
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<p>Spanish infantry fired on the balloon, which took so many hits that it was hauled down for repair. Enemy fire increased, and the balloon detachment was forced out of action for the rest of the battle. The men went to other duties.
