“The little scoundrel!”said Webb；“who could have supposed he was a spy？However，never mind about that；let us add up our particulars，such as they are，and see how the case stands to date.First，we've got a rebel spy in our midst，whom we know；secondly，we've got three more in our midst whom we don't know；thirdly，these spies have been introduced among us through the simple and easy process of enlisting as soldiers in the Union army—and evidently two of them have got sold at it，and been shipped off to the front；fourthly，there are assistant spies ‘outside'—number indefinite；fifthly，Wicklow has very important matter which he is afraid to communicate by the ‘present method'—will ‘try the other.'That is the case，as it now stands.Shall we collar Wicklow and make him confess？Or shall we catch the person who removes the letters from the stable and make him tell？Or shall we keep still and find out more？”
We decided upon the last course.We judged that we did not need to proceed to summary measures now，since it was evident that the conspirators were likely to wait till those two light infantry companies were out of the way.We fortified Sterne with pretty ample powers，and told him to use his best endeavors to find out Wicklow's “other method”of communication.We meant to play a bold game；and to this end we proposed to keep the spies in an unsuspecting state as long as possible.So we ordered Sterne to return to the stable immediately，and，if he found the coast clear，to conceal Wicklow's letter where it was before，and leave it there for the conspirators to get.
The night closed down without further event.It was cold and dark and sleety，with a raw wind blowing；still I turned out of my warm bed several times during the night，and went the rounds in person，to see that all was right and that every sentry was on the alert.I always found them wide awake and watchful；evidently whispers of mysterious dangers had been floating about，and the doubling of the guards had been a kind of indorsement of those rumors.Once，toward morning，I encountered Webb，breasting his way against the bitter wind，and learned then that he，also，had been the rounds several times to see that all was going right.
Next day's events hurried things up somewhat.Wicklow wrote another letter；Sterne preceded him to the stable and saw him deposit it；captured it as soon as Wicklow was out of the way，then slipped out and followed the little spy at a distance，with a detective in plain clothes at his own heels，for we thought it judicious to have the law's assistance handy in case of need.Wicklow went to the railway station，and waited around till the train from New York came in，then stood scanning the faces of the crowd as they poured out of the cars.Presently an aged gentleman，with green goggles and a cane，came limping along，stopped in Wicklow's neighborhood，and began to look about him expectantly.In an instant Wicklow darted forward，thrust an envelope into his hand，then glided away and disappeared in the throng.The next instant Sterne had snatched the letter；and as he hurried past the detective，he said:“Follow the old gentleman—don't lose sight of him.”Then Sterne skurried out with the crowd，and came straight to the fort.
We sat with closed doors，and instructed the guard outside to allow no interruption.
First we opened the letter captured at the stable.It read as follows:
HOLY ALLIANCEFound，in the usual gun，commands from the Master，left there last night，which set aside the instructions heretofore received from the subordinate quarter.Have left in the gun the usual indication that the commands reached the proper hand—
Webb，interrupting:“Isn't the boy under constant surveillance now？”
I said yes；he had been under strict surveillance ever since the capturing of his former letter.
“Then how could he put anything into a gun，or take anything out of it，and not get caught？”
“Well，”I said，“I don't like the look of that very well.”
“I don't either，”said Webb.“It simply means that there are conspirators among the very sentinels.Without their connivance in some way or other，the thing couldn't have been done.”
I sent for Rayburn，and ordered him to examine the batteries and see what he could find.The reading of the letter was then resumed：
The new commands are peremptory，and require that the MMMM shall be FFFFF at 3o'clock to-morrow morning.Two hundred will arrive，in small parties，by train and otherwise，from various directions，and will be at appointed place at right time.I will distribute the sign to-day.Success is apparently sure，though something must have got out，for the sentries have been doubled，and the chiefs went the rounds last night several times.W.W.comes from southerly to-day and will receive secret orders—by the other method.All six of you must be in 166at sharp 2a.m.You will find B.B.there，who will give you detailed instructions.Password same as last time，only reversed—put first syllable last and last syllable first.remember XXXX.Do not forget.Be of good heart；before the next sun rises you will be heroes；your fame will be permanent；you will have added a deathless page to history.amen.
“Thunder and Mars，”said Webb，“but we are getting into mighty hot quarters，as I look at it!”
I said there was no question but that things were beginning to wear a most serious aspect.Said I：