Lloyd shook his head. "I doubt if Schmidt can tell us much. He is too leaky a vessel for a clever spy to trust with valuable information."
"But," objected Symonds, "that is a very important paper you found in his possession to-night."
"True; but that paper does not furnish us with any clue as to the identity of the spy in Washington. Schmidt is simply a go-between like many other sutlers. Probably that paper passed through three or four hands before it was given to him to carry between the lines."
"Well, there is one thing certain; Baker will make Schmidt talk if any man can," declared Symonds. "May I ask, Captain, why we are headed for Poolesville?"
"Because I am looking for the man higher up. I expect to get some trace of the spy's identity in or around Poolesville."
"You may," acknowledged the Secret Service agent doubtfully; "and again you may not. Poolesville used to be called the 'rebs' post-office,' and they do say that word of every contemplated movement of McClellan's army was sent through that village to Leesburg by the 'grape-vine telegraph.'"
"Yes, I know," was the brief reply. The two men spoke in lowered tones as they made what speed they could among the trees. "By the way, Symonds, has it ever been discovered who it was delayed the despatch from Burnside, asking for the pontoon bridges?"
"No, never a trace, worse luck; but do you know," drawing his horse closer to his companion, "I think that and the Allen disaster were accomplished by one and the same person."
"Those two and a good many others we haven't yet heard of," agreed Lloyd. "In fact, it was to trace this particular unknown that I was recalled from service at the front by Pinkerton, and detailed to join the branch of the Secret Service under Colonel Baker."
"We have either arrested or frightened away most of the informers inside the city," volunteered Symonds, after a brief silence. "Besides which, Washington is too well guarded nowadays—two years ago was a different matter. Now, the general commanding the Maryland border patrols declares that a pigeon cannot fly across the Potomac without getting shot."