sword and, more slowly and cautiously now, groped his way along the western terrace.  He passed the row of bachelor quarters, and was well out beyond the limits of the fort before he came upon the next sentry,—­“Number Five,”—­and recognized, in the stern “Who comes there?” and the sharp rattle of the bayonet as it dropped to the charge, the well-known challenge of Private Leary, one of the oldest and most reliable soldiers in the regiment.

“All right on your post, Leary?” he asked, after having given the countersign.

“All right, I think, sor; though if the captain had asked me that half an hour ago I’d not have said so.  It was so dark I couldn’t see me hand afore me face, sor; but about half-past two I was walkin’ very slow down back of the quarters, whin just close by Loot’nant Jerrold’s back gate I seen somethin’ movin’, and as I come softly along it riz up, an’ sure I thought ‘twas the loot’nant himself, whin he seemed to catch sight o’ me or hear me, and he backed inside the gate an’ shut it.  I was sure ’twas he, he was so tall and slim like, an’ so I niver said a word until I got to thinkin’ over it, and then I couldn’t spake.  Sure if it had been the loot’nant he wouldn’t have backed away from a sintry; he’d ‘a’ come out bold and given the countersign; but I didn’t think o’ that.  It looked like him in the dark, an’ ‘twas his quarters, an’ I thought it was him, until I thought ag’in, and then, sor, I wint back and searched the yard; but there was no one there.”

“Hm!  Odd thing that, Leary!  Why didn’t you challenge at first?”

“Sure, sor, he lept inside the fince quick as iver we set eyes on each other.  He was bendin’ down, and I thought it was one of the hound pups when I first sighted him.”

“And he hasn’t been around since?”

“No, sor, nor nobody, till the officer of the day came along.”

Chester walked away puzzled.  Sibley was a most quiet and orderly garrison.  Night prowlers had never been heard from, especially over here at the south and southwest fronts.  The enlisted men going to or from town passed across the big, high bridge or went at once to their own quarters on the east and north.  This southwestern terrace behind the bachelors’ row was the most secluded spot on the whole post,—­so much so that when a fire broke out there among the fuel-heaps one sharp winter’s night a year agone it had wellnigh enveloped the whole line before its existence was discovered.  Indeed, not until after this occurrence was a sentry posted on that front at all; and, once ordered there, he had so little to do and was so comparatively sure to be undisturbed that the old soldiers eagerly sought the post in preference to any other, and were given it as a peace privilege.  For months, relief after relief tramped around the fort and found the terrace post as humdrum and silent as an empty church; but this night “Number Five” leaped suddenly into notoriety.