warn you that any attempt to escape will mean that some of you will get hurt."
He signalled to some of his confederates. These men unbound the captives' arms, and stood over them while they ate some coarse food that was brought into the small cave. They were given coffee to drink, and then, when the simple meal was over, they were securely bound again, and left to themselves, while the diamond makers went back to their machinery.
It was evident that they were going to attempt a big operation, for an unusually large quantity of the white stuff was prepared. The prisoners watched them idly. They could see some but not all of the operations. In this way several hours passed.
Gloom possessed the hearts of Tom and his friends. Not only had their expedition been almost a failure so far, but the young inventor was worried lest the gang might discover and wreck his airship. This would prove a serious loss. Lying there in the semi-darkness the lad imagined all sorts of unpleasant happenings.
At times he dozed off, as did the others. They had become somewhat used to the pain caused by the bonds, for their nerves were numb from the strain and pressure.
Once, as he was lightly sleeping, Tom was
