Where they went under this officer’s guidance, he cannot tell.  The tortuous tangle of alleys through which he now felt himself led was dark as the nether regions to his unaccustomed eyes.  There was snow under his feet and now and then he brushed against some obtruding object, or stumbled against a low fence; but beyond these slight miscalculations on his own part, he was a mere automaton in the hands of his eager guide, and only became his own man again when they suddenly stepped into an open yard and he could discern plainly before him the dark walls of a building pointed out by Sweetwater as their probable destination.  Yet even here they encountered some impediment which prohibited a close approach.  A wall or shed cut off their view of the building’s lower storey; and though somewhat startled at being left unceremoniously alone after just a whispered word of encouragement from the ever ready detective, George could quite understand the necessity which that person must feel for a quiet reconnoitering of the surroundings before the two of them ventured further forward in their possibly hazardous undertaking.  Yet the experience was none too pleasing to George, and he was very glad to hear Sweetwater’s whisper again at his ear, and to feel himself rescued from the pool of slush in which he had been left to stand.

“The approach is not all that can be desired,” remarked the detective as they entered what appeared to be a low shed.  “The broken board has been put back and securely nailed in place, and if I am not very much mistaken there is a fellow stationed in the yard who will want the pass-word too.  Looks shady to me.  I’ll have something to tell the chief when I get back.”

“But we!  What are we going to do if we cannot get in front or rear?”

“We’re going to wait right here in the hopes of catching a glimpse of our man as he comes out,” returned the detective, drawing George towards a low window overlooking the yard he had described as sentinelled.  “He will have to pass directly under this window on his way to the alley,” Sweetwater went on to explain, “and if I can only raise it—­but the noise would give us away.  I can’t do that.”

“Perhaps it swings on hinges,” suggested George.  “It looks like that sort of a window.”

“If it should—­well! it does.  We’re in great luck, sir.  But before I pull it open, remember that from the moment I unlatch it, everything said or done here can be heard in the adjoining yard.  So no whispers and no unnecessary movements.  When you hear him coming, as sooner or later you certainly will, fall carefully to your knees and lean out just far enough to catch a glimpse of him before he steps down from the porch.  If he stops to light his cigar or to pass a few words with some of the men he will leave behind, you may get a plain enough view of his face or figure to identify him.  The light is burning low in that rear hall, but it will do.  If it does not,—­if you can’t see him or if you do, don’t hang out of the window more than a second.  Duck after your first look.  I don’t want to be caught at this job with no better opportunity for escape than we have here.  Can you remember all that?”