A balloonist nails his mark
By the end of September, the war appeared that it might be heating up again. Maj. General George McClellan, commander of the Army of the Potomac, had been saying for over a month that a massive Confederate attack was imminent. He predicted the attack would come from Leesburg, and drive up towards notoriously disloyal Baltimore, cutting Washington off from the rest of the country and trapping his newborn army.
And now, with an engagement at Lewinsville, and a series of skirmishes along the length of the Potomac River from Great Falls to Point of Rocks, it appeared that the Confederates might be feeling out the Union position to prepare for that big strike. His process of collecting the many brigades of the army into divisions so that they would be easier to handle in battle had certainly brought the most benefit to his friends and hand-picked proteges so far, but he had also given clear priority to defending the Potomac River line.
The divisions of Irvin McDowell, William Franklin, Fitz John Porter, and Don Carlos Buell all defended Alexandria and the direct approaches into the capital city, while those of George McCall, Charles P. Stone, and Nathaniel P. Banks guarded against a Potomac crossing as far as Williamsport. The brigades not stationed along the Potomac still waited to be grouped into divisions, and as far as McClellan was concerned they could keep waiting.
The Confederate Army of the Potomac under General Joseph E. Johnston could barely keep itself supplied and maintaining the close presence to Washington it had kept since its victory at Manassas. There was no way it was going to advance, in fact, Johnson was interested in pulling it back behind Bull Run. But McClellan was looking for confirmation of a conviction, and easily found plenty of evidence that might support it.
On the morning of September 24, one of the few remaining independent brigades along the Potomac, that of Brig. General W.F. "Baldy" Smith embarked on a scheme to try to shake the Confederates from their close hold on Washington. The most pesky of Smith's problems had been cavalry who darted about, took prisoners, recorded troop numbers, and in general annoyed him. They were under the direction of Colonel J.E.B. Stuart, headquartered on Munson Hill, close to the high school that bears his name today.
What made Smith's plan different than the classic artillery bombardment was the addition of balloons. Thaddeus Lowe - balloonist, inventer, shameless self-promoter - had been working hard at winning the approval of McClellan's generals since he had been unable to get the War Department to be enthusiastic about his new technology. He found a true believer in Fitz John Porter, a close confidant of McClellan and one of the fourth division commander to be named.
Porter had asked Lowe to draw up a plan for a Balloon Corps to help with observation. Lowe dutifully submitted an ambitious plan for four balloons and portable gas generators for inflation. To his delight, Porter sent it forward to McClellan with a recommendation of support. There it met a request from Baldy Smith for observation balloons that had also been inspired by Lowe.
Smith, formerly a West Point mathematics professor, had latched onto the idea that his smoothbore howitzers and rifled Parrott guns should have the range to hit Munson Hill, but the terrain made it impossible to use them without exposing them to counter-fire and Stuart's cavalry. So without hearing back from McClellan, he and Lowe decided to send a balloon aloft to direct the artillery fire and prove the value of the new technology.
Lowe ascended 1,000 feet into the air (nearly twice the height of the Washington Monument) and he sent signals to Smith to adjust the fire appropriately (it was too high for the telegraph wire to be strung). "Battery marksmen," he recorded later in a somewhat self-serving account of the affair, "without seeing who or what he was firing at, by merely watching me, made such an accurate fire that the enemy was demoralized."
While the demoralization of the enemy may have been the subject of opinion, the value of directing artillery fire by aerial observation appeared definite to McClellan. Another event on September 24 underscored it. At mid-day a Confederate force attacked the 28th Pennsylvania Volunteer Infantry Regiment at Point of Rocks. "The reconnaissance [reported earlier] proved to be an attack by from 100 to 200 of the enemy, supported by about 400 secreted in the woods," Colonel John Geary reported to Banks, his division commander.
The attack was made by musketry, from the opposite side of the river, in the vicinity of the ruins of the bridge at Point of Rocks. They fired about 200 shots, nearly all of which fell short and without injury. We answered promptly with shell and rifles and silenced them in a few minutes; what loss on their side I cannot say positively.As the report made its way up to McClellan, he surely must have agreed with Geary's assessment:
[The Southerners launch] reconnaissances or menaces with the recurrence of every favorable opportunity, and I am well aware that only by our vigilance and promptitude will our advantages and position be maintained. Only three days since I discovered them surveying my camp from every available point, purposing, as I have reason to believe to assault us by artillery from an eligible position on the table or plateau on the Virginia side.September 25, Thaddeus Lowe was notified by the U.S. Army's Quartermaster General that McClellan intended to purchase according to his plan.