<p>La Mountain left temporarily on 16 August to get a larger balloon and his own gas generator. He left the letter (quoted in part at the beginning) with General Butler, who passed it along with a strong endorsement to the War Department. Butler moved to another command, his successor was not told of La Mountain's service, and so when the aeronaut did return with his larger balloon, nobody was expecting him. Finally he was ordered to report to the Army of the Potomac, under Major General George B. McClellan. There his path crossed that of Thaddeus S. C. Lowe, and fireworks followed.
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<p>Lowe was 29 years old, and experienced as a balloonist. He also had planned to fly the Atlantic. On a test ascent he had lifted off from Cincinnati, Ohio, a Union stronghold, and had landed well to the south in secessionist territory. Suspected of being a spy, he was jailed, and the abolitionist newspapers he was carrying with him didn't help his case. But his fame had preceded him; he was recognized, released and returned to Cincinnati. He abandoned the transatlantic venture and volunteered to join the Union, with his balloons.
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<p>In Washington, on 18 June 1861, he demonstrated the use of captive balloons for observation and telegraphed a message from his 'Enterprise' to the White House, relayed by the Alexandria office of the telegraph company. The next day, Lowe made ascensions from the White House lawn, watched by President Abraham Lincoln and Cabinet members.
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<p>Lincoln was fascinated, and wrote letters of introduction to General Scott on Lowe's behalf. But he finally had to escort Lowe personally into the office of the crusty old general to persuade him to hire Lowe and his new-fangled contraption. Lowe began work on a 25,000-cu ft (708-m<su>3</su>) balloon on 2 August, and started drawing a daily pay of $5, to be increased to $10 when the balloon was complete and operating.
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<p>The 'Union' first flew on 29 August outside Washington. On 24 September, Lowe first directed artillery fire by Union batteries, advising them of the position of their shots around targets in the Falls Church area. The following day, the Army Quartermaster General ordered four more new balloons from Lowe, together with the gas generating plants necessary to inflate them.
