They pressed on steadily along the rough, rudely made floor, on and on and on, the little torch showing always the few feet in front of them, to safeguard them against any pitfalls that might be laid for the unwary traveller.  It seemed hours that they walked thus, and their wonder at the elaborateness of this extraordinary tunnel system grew.  There were turnings every now and again, passageways branching off from the main one into other patches of unbroken gloom.  And it was a ticklish job at best.  At any moment someone might round the next corner and come upon them, and then—­the game would be up with a vengeance.  At Dollops’s suggestion they followed always the turnings upon the right.

“Always keep to the right, sir, and you’ll never go far wrong—­that’s what they teaches you in Lunnon.  An’ that’s what I always follows.  It’s no use gittin’ lost.  So best make a set rule and foller it.”

“Well, at any rate there’s no harm in doing so,” responded Cleek a little glumly.  “We don’t know the way out and we might as well try one plan as another.  Seems pretty well closed up for the night, doesn’t it?  It certainly is a passage and if the door at the other end is impassable after all this wandering, I’ll, I’ll—­I don’t know.”

“Carn’t do no good by worritin’, sir.  Just ’ave to carry on—­that’s all we kin do,” responded Dollops, with some effort at comfort.  “There’s summink in front of us now.  Looks like the end of the blinkin’ cage, don’t it?  Better investigate afore we ’it it too hard, sir.”

“You’re right, Dollops.”

Cleek stepped cautiously forward into the gloom, lighting it up as he progressed, the rays of his tiny torch always some five feet ahead of him.  And the end it proved to be, in every sense of the word.  For here, leading upward as the other had done, was a similar little flight of clay-hewn steps, while at the top of them—­Cleek gave a long sigh of relief—­showed a square of indigo, a couple of stars and—­escape at last.

“Thank God!” murmured Cleek, as they mounted the rough steps and came out into the open air, with the free sky above them and a fine wind blowing that soon dispelled the effects of their underground journey.  “Gad! it’s good to smell the fresh air again—­eh, Dollops?  Where on earth are we?  I say—­look over there, will you?”

Dollops looked; then gasped in wonder, astonishment, and considerable awe.

“The Flames, guv’nor—­the blinkin’ Frozen Flames!”

Cleek laughed.

“Yes.  The Flames all right, Dollops.  And nearer than we’ve seen ’em, too!  We must be right in the middle of the Fens, from the appearance of those lights, so, all told, we’ve done a mile or more underground, which isn’t so bad, my lad, when you come to look at the time.”  He brought out his watch and surveyed it in the moonlight.  “H’m.  Ten past eleven.  You’ll have to look sharp, boy, if you’re to get to the docks by twelve.  We’ve a good four miles’ walk ahead of us, and—­what was that?”