In the war with Mexico which began on May 13 one hundred years ago, American troops used rockets in the storming of Chapultepec, ancient fortress in the suburbs of Mexico City. The Battle, fought on Sept.13, 1847, was the last important conflict of the war. Two thousand of the new rockets were fired at the Mexicans. They had three curved vanes, in place of the straight stick, which made them spin and pursue a more direct and longer flight. These rockets were used principally to aid in the landing of troops at Vera Cruza and in storming Chapultepec. (AP Photo)