|A limbered 12-pounder howitzer, Model 1841 (LOC)|
The officer in charge of the Pennsylvania militia guarding Edwards' Ferry had estimated there were between 800 and 900 Confederates. As with most early war estimates from jumpy, inexperienced officers, the number was probably high, since the men were from Colonel Eppa Hunton's 8th Virginia Infantry (though Stone didn't know this), which numbered only between 800 and 900 men total. Hunton had been on his own since May, when Virginia's Governor, John Letcher, had asked him to raise the regiment in the Leesburg area. For about two weeks he had reported directly to Robert E. Lee (as the former head of Virginia militia), until Lee had directed him to report to G.T. Beauregard in Manassas (on the same day Stone had originally set out from Washington for Rockville).
Hunton's reports didn't survive the war, like many Confederate papers. When Richmond fell in 1865, the city burned and government employees hid documents wherever they thought was safe. When the U.S. Congress established the Official Records of the War of the Rebellion in 1866 the Union archives from the War Department were transferred en masse to the project, but Confederate sources were harder to find or coax their possessors to turn them over to the U.S. Government.
So we only have Stone's account of what happened on the evening of June 18.
They [the Confederates] made use of the ferry boat, which they had drawn from the Potomac. I had given orders that on any attempt to move the boat fires should be opened on it, and in-compliance with these orders Lieutenant Hasbrouck fired from his 12-pounder field howitzer a spherical case shot, which burst directly in range and covered the boat with a shower of bullets and fragments. The effect was excellent.
One of the officers (doubtfully Hunton himself) had been mounted on the ferry boat. The shot scared his horse, who jumped in the river, drenching the man. The whole expedition returned to their side of the creek and began to form up lines until Hasbrouck's cannon launched another shell in their midst and sent them scurrying to safer ground.
"I deemed it important to prevent communication along the river between these forces and those opposite Lieutenant Colonel Everett's position" at Seneca Creek, he explained dryly. Stone's matter-of-fact prose conceals what most have been serious concern. By forcing the Confederates opposite Edwards' Ferry at Leesburg to travel inland to the next bridge over Goose Creek before reaching the point opposite Seneca Creek (today the site of Trump National Golf Club), he reduced the mobility of the unknown number of Confederates, which might buy him a few hours in the event of the concerted attack that felt imminent.
The rest of Stone's report betrays his concern. He pledges to send a "trusted, hired messenger" to the still-missing Robert Patterson somewhere around Harper's Ferry, but then sends a very detailed request for ammunition for his two guns from the West Point battery - a group of cadets that had been recruited by their cantankerous artillery professor Charles Griffin. Throughout the Rockville Expedition Stone had complained about his lack of artillery, asking that the remaining four of Griffin's guns be sent to him, but knowing that Joe Johnston's army had vanished from Harper's Ferry and that Washington was suddenly demanding he send a full regiment back as quickly as possible and the Confederates were more organized at Leesburg, Stone has obviously put the pieces together -- an attack is imminent and there are no reinforcements to be had.
The report also gives us our first opportunity to identify Stone's two guns (guns are always artillery, in military terminology -- soldiers carry arms, muskets, pistols, or rifles, never guns). The 12-pounder howitzer and 6-pounder cannon were a classic artillery duo in the pre-Civil War army. Both were bronze smoothbores that lacked the endurance, distance and accuracy of the iron rifled guns that would take their place as the war continued (they were already considered obsolete by 1861). The weight described the weight of a ball that could be shot from the gun. The howitzer was a shorter gun, that fired exploding shells at a high trajectory, perfect for jobs like showering Eppa Hunton's men with shot when they were trying to cross.
The 6-pounder cannon was, like the howitzer, last updated in 1841 (it's possible that the two guns on Stone's expedition had fought in the Mexican War). While the howitzer's maximum range was about three-quarters of a mile, the 6-pounder could make it over four-fifths of a mile. Both guns were being replaced by the 12-pounder "Napoleon" bronze, smoothbore cannon, developed by the French Emperor, Napoleon III in 1856, which litters today's Civil War battlefields (look for the green cannon, they're almost certainly Napoleons) and the 10-pounder rifled Parrott gun, which could shoot a mile and a quarter with amazing accuracy (these guns are usually the black cannon on Civil War battlefields, look for the distinctive iron hoop around the back of the gun).
It was these two obsolete guns, the militia, and his regiment of U.S. regulars that Stone might have to count on to resist an attack by at least 15,000 Confederates. As he had outlined a few days earlier, his best option was going to be a bloody, fighting retreat towards Georgetown.