"Shall we take wood down there, Harry?"

"No; I think a fire would be a drawback rather than an assistance. It would be very valuable if we were working at one spot, but it could give no general light in a place a hundred feet long. We will take a torch down, and hold it and sweep by turns. We shall only want, to begin with, to make a clear path a couple of feet wide down the middle. Of course later on we shall clear it all. That will be sufficient to enable us to see how the floor is constructed, whether with big blocks or small ones, how closely they are fitted together, and so on. It is certainly unlikely that we shall find any indication as to where chambers exist."

It took but a very short time to clear the path; the dust was so light that one sweep of the broom cleared it away. When they got to the farther end they returned to examine the floor. For four or five feet from the cistern the rock had been evidently untouched, except to cut off any projecting points. Then there was a clear line running across the path. Bertie held the torch down close to it. Harry knelt down and examined it.