Thaddeus Lowe's balloon test of the "Intrepid" May 31, 1862, at the battle of Fair Oaks, Virginia, during the Peninsular Campaign, May-August 1862. Lowe's balloon was used for reconnaissance for the Union Army during the Civil War. Using a telegraph the driver could send a message about Confederate camps and troop movements to soldiers below who then gave the information to Union generals. The test was supported by Smithsonian Institution Secretary Joseph Henry, who served as President Abraham Lincoln's scientific advisor during the war.