yndham to assassinate Mosby. Eventually Mosby proposed a test of
Ames' sincerity. The deserter should guide the company to a Union
picket post, and should accompany the raiders unarmed: Mosby would
ride behind him, ready to shoot him at the first sign of treachery.
The others agreed to judge the new recruit by his conduct on the raid.
A fairly strong post, at a schoolhouse at Thompson's Corners, was
selected as the objective, and they set out, sixteen men beside Ames
and Mosby, through a storm of rain and sleet. Stopping at a nearby
farm, Mosby learned that the post had been heavily re-enforced since
he had last raided it. There were now about a hundred men at the
schoolhouse.

Pleased at this evidence that his campaign to force the enemy to
increase his guard was bearing fruit, Mosby decided to abandon his
customary tactics of dismounting at a distance and approaching on
foot. On a night like this, the enemy would not be expecting him, so
the raiders advanced boldly along the road, Mosby telling Ames to make
whatever answer he thought would be believed in case they were
challenged. However, a couple of trigger-happy vedettes let off their
carbines at them, yelled, "The Rebs are coming!" and galloped for the
schoolhouse.

There was nothing to do but gallop after them, and Mosby and his band
came pelting in on the heels of the vedettes. Hitherto, his raids had
been more or less bloodless, but this time he had a fight on his
hands, and if the men in the schoolhouse had stayed inside and
defended themselves with carbine fire, they would have driven off the
attack. Instead, however, they rushed outside, each man trying to
mount his horse. A lieutenant and seven men were killed, about twice
that number wounded, and five prisoners were taken. The rest,
believing themselves attacked by about twice their own strength,
scattered into the woods and got away.

Ames, who had ridden unarmed, flung himself upon a Union cavalryman at
the first collision and disarmed him, then threw himself into the
fight with the captured saber. His conduct during the brief battle at
the schoolhouse was such as to remove from everybody's mind the
suspicion that his conversion to the Confederate cause was anything
but genuine. Thereafter, he was accepted as a Mosby man.

He was accepted by Mosby himself as a veritable godsend, since he was
acquainted with the location of every Union force in Fairfax County,
and knew of a corridor by which it would